New England Fishery Management Council

Transcription

1 New England Fishery Management Council 50 WATER STREET NEWBURYPORT, MASSACHUSETTS PHONE FAX C.M. Rip Cunningham, Jr., Chairman Paul J. Howard, Executive Director MEMORANDUM DATE: August 17, 2012 TO: Habitat Committee FROM: Michelle Bachman SUBJECT: Adverse Effects discussion materials for August 23 meeting This packet contains the following materials: 4. Memo from the Habitat PDT outlining EFH management issues stemming from the August 2 Groundfish Committee Motion 5. Ground cable options discussion document outlining the range of ground cable management options and discussing challenges associated with the analysis of these types of options 6. Updated recommendations about dedicated habitat research areas PowerPoint presentation prepared by the PDT At the meeting, I will review the memo about the Groundfish Committee motion and the ground cable document. Dr. Auster and I will give the DHRA presentation. A document describing the current range of adverse effects minimization options can be found on the Council s website: Note that the gear modifications section of this document (section 3.2.2) was updated to produce document 5.

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3 New England Fishery Management Council 50 WATER STREET NEWBURYPORT, MASSACHUSETTS PHONE FAX C.M. Rip Cunningham, Jr., Chairman Paul J. Howard, Executive Director MEMORANDUM DATE: August 17, 2012 TO: Habitat Committee FROM: Habitat Plan Development Team SUBJECT: Implications of Groundfish Committee closed area motion for EFH management The Groundfish Committee approved the following motion, which has implications for EFH management, at their August 2 meeting: 1. Open the NLCA year round. 2. Open CAI from May 1 through February 15 for selective fishing gear i 3. Open CAII south of 41-50N from May 1 through February 15 for the use of selective fishing gear i 4. Open the WGOM closed area, except for an area referred to as Jeffreys Ledge on page 5 of a Habitat PDT memo dated August 15, 2011 ii 5. Open the Cashes Ledge Closed Area year round except for an area around Ammen Rock identified as Habitat Area consistent with the Habitat PDT recommendation #4 on page 3 of the Habitat PDT memo dated August 15, 2011 ii i. Selective gear was clarified to mean Ruhle trawls, separator trawls, etc., as well as longline gear, but not sink gillnets and in the case of CAI and CAII, not recreational gear. ii. Items 4 and 5 might be modified slightly based on minor changes made by the Habitat PDT to these areas since last August. The areas affected by this motion are shown in Figure 1. This figure reflects the Habitat PDT s assumptions about the intent of the motion. We assumed that the Committee s intent was that the groundfish and habitat closures in NLCA, CAI, CAII, WGOM, and CL would be opened, and that the only areas that would remain closed year round would be the area north of in Closed Area II, the Jeffreys Ledge Area, and the Ammen Rock Area. Note that specific boundaries for the Ammen Rock area were not drafted until later, and were first presented to the Committee in January 2012, so charts associated with the August 15 PDT meeting summary only show the Cashes Ledge habitat closure and a modified version of the Cashes Ledge habitat closure, both of which are distinct from the Ammen Rock area. Further, as it was not mentioned in the motion, the PDT assumed that the Jeffreys Bank habitat closure would be maintained. This motion represents only one of many possible area management alternatives to meet groundfishrelated objectives that might be proposed during the development process for Omnibus EFH Amendment 2 (OA2). The PDT recognizes that the process of developing these alternatives is ongoing. The PDT also recognizes that the Groundfish Committee motion requires Council approval for inclusion in the current groundfish framework adjustment (FW48), or another action that is distinct from OA2. That being said, if the area management scenario depicted in Figure 1 was implemented as shown, it would conflict with the following adverse effects minimization options approved by the Habitat Committee because it would reopen the following areas that are currently closed:

4 Cashes Ledge Adverse Effects Minimization Area (updated boundaries/reduced in size from the current Cashes Ledge habitat closure area, with the western boundary modified to 69 W longitude; currently a mobile bottom tending gear habitat closure, closed since 2002) Fippennies Ledge Adverse Effects Minimization Area (currently within the Cashes Ledge groundfish closure but not within a habitat closure; mobile bottom tending gears have been excluded since year 2002 as gears capable of catching groundfish) Stellwagen Bank Adverse Effects Minimization Area (currently a mobile bottom tending gear habitat closure, closed since 1998) These potential openings are of concern to the Habitat PDT, because these areas have been identified via the OA2 process as locations considered vulnerable to the adverse effects from fishing on EFH. Fishing in these areas, even for a single year, reverses years of seafloor habitat recovery. Current research indicates that this recovery is ongoing. Other adverse effects minimization areas approved by the Habitat Committee are maintained as closures within the Groundfish Committee alternative: Jeffreys Ledge Adverse Effects Minimization Area (within WGOM habitat closure) Ammen Rock Adverse Effects Minimization Area (within Cashes Ledge habitat closure) There are other adverse effects minimization options approved by the Habitat Committee that were not addressed by the motion because they lie outside the boundaries of current closed areas. Georges Shoal (2 subareas as possible MBTG restricted areas) West of Great South Channel (4 subareas as possible MBTG restricted areas) Cox Ledge (2 subareas as possible MBTG restricted areas) Some of the existing habitat closures would remain under the Groundfish Committee alternative. Closed Area II north of (this area includes the entire habitat closed area and part of the groundfish closure). The Habitat Committee previously approved two options: (1) keep this area as-is, or (2) eliminate the area. Jeffreys Bank habitat closure. The Habitat Committee previously approved two options: (1) keep this area as-is, or (2) modify the area boundaries. Figure 2 shows the no action areas and Figure 3 shows the adverse effects minimization areas. For the most up to date version of the adverse effects options developed by the Habitat Plan Development Team and Committee, see A goal of OA2 is to minimize the adverse effects of fishing on habitat across all fishery management plans. The PDT recommends the following actions in order to move towards reconciliation/optimization of multiple objectives. The Habitat Committee may wish to convey recommendations 1 and 2 to the Council at their September 2012 meeting: 1. That the Council analyze the Stellwagen Bank, Fippennies Ledge, and modified Cashes Ledge adverse effects minimization areas in whichever action(s) consider access to the groundfish and habitat closures (FW48, OA2, and/or another action), as mobile bottom tending gear closures to minimize the adverse effects of fishing on EFH. All of these areas are within existing habitat closures or groundfish closures and would be opened to groundfishing activities if the August 2

5 groundfish motion is implemented as shown in Figure 1. These areas were refined via the Habitat Committee process to promote fishing access while minimizing adverse effects. 2. Support the Groundfish Committee recommendation that the Council analyze the Jeffreys Ledge and Ammen Rock adverse effects minimization areas in whichever action(s) consider access to the groundfish and habitat closures (FW48, OA2, and/or another action), as habitat closures to minimize the adverse effects of fishing on EFH. The Jeffreys Ledge area was intended as a mobile bottom tending gear closure. The Ammen Rock area was intended as a closure to all gears that can be managed by the Council, as well as a request to the Commission for consideration for closure to lobster traps. These areas were refined via the Habitat Committee process to promote fishing access while minimizing adverse effects. 3. Within the context of OA2, the PDT recommends analysis of both Platts Bank subareas, the east and west Georges Shoal areas, all four Great South Channel subareas, and both Cox Ledge subareas in OA2 as mobile bottom tending gear closures to minimize the adverse effects of fishing on EFH. These areas were refined via the Habitat Committee process to promote fishing access while minimizing adverse effects. The PDT recommends further that the Committee and Council consider tradeoffs between the two Georges Shoal areas and CAII habitat closure in terms of balancing fishing access and adverse effects minimization objectives. More specifically, given similarities in the habitat types in the two areas, maintaining the current area or a portion thereof might be preferable over the new areas from an adverse effects minimization perspective. Analyses will need to be completed to fully explore the costs and benefits. 4. Within the context of OA2, the PDT does not recommend further consideration of ground cable length limit (gear modification) options at this time. A separate discussion document outlines the rationale behind this recommendation. 5. Within the context of OA2, the PDT does recommend considering dedicated habitat research areas in conjunction with the adverse effects minimization areas. A separate PowerPoint presentation and accompanying memorandum outline the most recent thinking on research area design and requests a range of feedback from the Committee so that the PDT can proceed further. See figures below Figure 1. Groundfish Committee motion. Increases access to currently closed areas. Omnibus EFH A2 analyses completed to date indicate that this alternative will not minimize the adverse effects of fishing on EFH. Figure 2. No action groundfish and habitat closures. Figure 3. Adverse effects minimization areas proposed as mobile bottom-tending gear closures.

6 71 0'0"W 70 0'0"W 69 0'0"W 68 0'0"W 67 0'0"W CAII habitat closure Jeffreys Bank habitat closure Current groundfish closures Current habitat closures Selective Gear Areas - seasonal Groundfish closure - year round Ammen Rock Adverse Effects Area Jeffreys Ledge Adverse Effects Area CONTOUR, Meters '0"N 44 0'0"N Jeffreys Bank Jeffreys Ledge Ammen Rock 43 0'0"N 42 0'0"N Closed Area II Closed Area I 41 0'0"N 40 0'0"N New England Fishery Management Council Habitat Plan Development Team Map date: 10 August 2012 NAD 1983 UTM Zone 19N Nautical Miles

7 71 0'0"W 70 0'0"W 69 0'0"W 68 0'0"W 67 0'0"W Habitat Closures Groundfish Closures CONTOUR, Meters '0"N 44 0'0"N 43 0'0"N Cashes Ledge WGoM 42 0'0"N Closed Area II Closed Area I 41 0'0"N Nantucket Lightship 40 0'0"N New England Fishery Management Council Habitat Plan Development Team Map date: 10 August 2012 NAD 1983 UTM Zone 19N Nautical Miles

8 71 0'0"W 70 0'0"W 69 0'0"W 68 0'0"W 67 0'0"W Ammen Rock Jeffreys Ledge Cashes Ledge mod 45 0'0"N Fippennies Stellwagen Jeffreys Bank mod Platts Bank Georges Shoal West of GSC Cox Ledge 44 0'0"N CONTOUR, Meters Current habitat closures Current groundfish closures Jeffreys Bank modified Platts Bank 1 Platts Bank 2 Jeffreys Ledge Cashes Ledge modified Fippennies Ledge Ammen Rock 43 0'0"N Stellwagen Georges Shoal East 42 0'0"N Chatham Light Georges Shoal West Great Rip Cox Ledge 2 Cox Ledge 1 North of Davis Bank North of Fishing Rip 41 0'0"N 40 0'0"N New England Fishery Management Council Habitat Plan Development Team Map date: 10 August 2012 NAD 1983 UTM Zone 19N Nautical Miles

9 Discussion document: Gear modification options to minimize the adverse effects of fishing on EFH Background, previous discussions, and practicability and analytical considerations 1.0 Introduction Gear modifications could be used to minimize the adverse effects of fishing on benthic habitats. For bottom otter trawls, a maximum ground gear size on the sweep and/or a maximum ground cable length could be employed. Limiting ground gear size would be expected to reduce seabed impact by making it difficult to fish bottom otter trawls over areas of complex relief, thereby redirecting fishing effort into less complex habitats. Limiting ground cable length would be expected to reduce the linear effective width of the gear and thereby the area swept and associated seabed impacts. These statements are oversimplifications, however, and a full accounting of the costs and benefits to habitat, managed species, and the fishing industry should be undertaken in order to more fully balance habitat, resource, and economic considerations associated with gear modifications. Currently, ground gear restrictions are used in two large areas. The inshore GOM roller gear restricted area covers over 11,000 km 2 in the western GOM and has a 12 inch ground gear size limit. A 6 inch size limit is in place in the southern monkfish area for vessels operating on a monkfish DAS. The southern monkfish area covers a very large area: all areas south of 41 N latitude east of Cape Cod; plus all areas to the south and west of Cape Cod. Ground cable length limits are in place in the northern shrimp fishery, which is managed by ASMFC. 2.0 Previous Habitat Committee and PDT discussions In the context of minimizing adverse effects, gear modification requirements were first considered by the Habitat Committee at their June 2010 meeting, within the LISA 1 clusters in the Gulf of Maine (GOM), on Georges Bank (GB), and in Southern New England (SNE). The Committee reiterated their desire for analysis of both ground cable and roller gear restrictions in GOM clusters 1, 3, and 4 at their October 2010 meeting. At their October 2010 meeting, the Committee agreed to provide some recommendations to the PDT about an appropriate range of options for ground cable lengths, but at the current time, specific length options need further development by the PDT and Committee. During their June 2011 meeting, the PDT reviewed the LISA cluster results and other non-sasi information, and recommended a range of vulnerable areas to the Committee as candidate areas for adverse effects minimization measures. At their July 2011 meeting, the Committee recommended analyzing mobile bottom tending gear closures and ground cable restrictions in potential management areas designed to encompass gravel hotspots identified by the PDT on and west of Georges Shoal. Also at that meeting, they recommended analysis of ground cable length restrictions in lieu of the current mobile bottom tending gear closure in the existing Closed Area I habitat areas. Specifically, the ground cable options would set a maximum total ground cable length for trawl vessels operating in a particular spatial area. 1 Local Indicators of Spatial Association analysis of Swept Area Seabed Impact model outputs

10 At their August 2011 meeting, the PDT recommended ground cable length restrictions only in a large area on Georges Shoal and in a large area combining four separate gravel hotspots west of the Great South Channel. At their August 2011 meeting, the Committee recommended analyzing ground cable restrictions for three areas on and west of Georges Shoal (Georges Shoal Large, as recommended by the PDT for this purpose, Georges Shoal East area developed at the meeting, and a Georges Shoal West area combining the two westernmost gravel hotspots). The Committee also recommended ground cable restrictions be analyzed for the four Great South Channel areas individually, and a single Cox Ledge area, and reiterated their support for the analysis of the existing CAI habitat areas as ground cable modification areas. At their June 2012 meeting, the Habitat Committee added a ground cable length limit option for all of the GOM areas, with the exception of the Ammen Rock subsection of the Cashes Ledge area. These include the new and modified areas on Jeffreys Bank, Cashes Ledge, Fippennies Ledge, Platts Bank, Jeffreys Ledge, and Stellwagen, and the existing WGOM, Jeffreys Bank, and Cashes Ledge habitat closures. The following gear modification options are currently under consideration by the Habitat Committee. Note that the sizes of the existing and proposed management areas vary widely; there are larger and smaller management areas existing and proposed throughout the region in the Gulf of Maine, on Georges Bank, and in Southern New England. These options could be implemented separately or combined and the intention is to combine these options with mobile bottom tending gear closure options into packaged suites of alternatives (as opposed to a completely a la carte approach). Existing mobile bottom tending gear habitat closures with options (as of 6/8/12) to be converted to ground cable length limited areas: Jeffreys Bank Cashes Ledge Closed Area I (two areas) New habitat management areas with options (as of 6/8/12) to be converted to ground cable length limited areas: Jeffreys Bank (modified) Cashes Ledge (modified) Fippennies Ledge Platts Bank areas (2) Jeffreys Ledge (subset of current WGOM habitat area) Stellwagen Bank (subset of current WGOM habitat area) Georges Shoal areas (3) Great South Channel areas (4) Cox Ledge areas (2)

11 Based on the current range of adverse effects minimization options, the remainder of this document focuses on the potential costs and benefits of implementing ground cable length limits. 3.0 Ground cables and their use Ground cables are defined as wire ropes extending along the seabed between the trawl doors and the bridles or net; for the purpose of herding fish and increasing the area of seabed fished (swept) by the trawl gear. Ground cable diameter can be increased be passing the wires through rubber disks (cookies) or rollers; this modification is designed to assist passage of the ground cables over the seabed. Figure 1 - Ground cable with cookies Ground cables are typically constructed from steel wire rope (twisted), often with small diameter rubber disks (cookies) compressed together along the entire cable length (Figure 1). There are some reports that a few fishermen use chain as an alternative to wire rope. Cable diameter ranges from 9/16 in to ¾ in, with 1¾ to 3 in diameter cookies (2 in to 2 3/8 in cookies are commonly used). Ground cable length varies between boats and typically is ftm ( m) although some larger boats may use up to 120 ftm (219 m). Generally, longer lengths are used on smooth seabeds, when the risk of hooking up on obstacles is small, and/or when targeting flatfish. Inshore boats (which also tend to be smaller) tend to use shorter ground cables (30 50 ftm, m) so they can maneuver the trawl gear around rocky outcrops and other obstructions that can catch or damage the gear. Some fishermen do not vary ground cable length much under different circumstances as it affects the herding angle of the cables and catch rates. Others have been known to add or remove substantial lengths to their ground cables; however it is not known if this is a regular or infrequent activity, or the circumstances that result in such a change. It appears that there is little variation in cable/cookie composition when targeting groundfish, although a small number of fishermen may change ground cables when changing nets. 4.0 Practicability and analytical considerations In comparison with the sweep and the doors, ground cables are the longest element of bottom trawl gear and thus they contribute the greatest proportion of area swept for a given fishing event (Figure 2). Thus, shortening their length and/or reducing their contact with the seabed provides a mechanism to reduce overall area swept and bottom contact, thereby decreasing the adverse effects of fishing on EFH.

12 Figure 2 - Schematic of trawl gear (top down view) showing the relative contribution of doors vs. ground cables vs. sweep to area swept. Not to scale. Given some straightforward assumptions about angle of attack, and holding all else constant, it is relatively simple to estimate the reductions in linear effective gear width that could result from shortened cable lengths, and to then use these reduced area swept estimates in the SASI model to estimate changes in adverse effects within the location of the gear restrictions. However, in order to understand if there is a net benefit for use of these types of gear modifications to minimize total area swept, other information would need to be incorporated into the analysis, such as: The cable length/catchability trade-off for target species. If catchability is reduced with shortened cables, does tow length/duration increase to compensate? Would gear modifications lead to a net increase or decrease in area swept, and thus EFH adverse effects, within restricted areas because of the trade-off between CPUE and ground cable length? The distribution of effort after gear restrictions are enforced. Will shortened cable lengths actually restrict use of gear in those habitats we are targeting for conservation? What degree of reduction in catchability will lead a vessel to simply fish elsewhere, rather than within the restricted ground cable area? The answers depend on our ability to estimate likely changes in behavior, and the spatial distribution of fishing effort, for use in the SASI model. The scope of use for the modified gear. Are there ground cable length reductions that achieve EFH protection goals and cause insignificant enough changes in catchability, such that fishermen use these nets in all fishing areas? If this is not the case, and fishermen carry two separate nets on board, the associated increases in costs to maintain the additional gear would need to be calculated when estimating impacts to the fishing industry. In summary, looking more holistically at fishing across a full suite of managed and unmanaged areas, reductions in either the amount of fishing effort or the catch rates inside a ground cable area could lead to increased fishing effort in other locations. The size and direction of changes in adverse effect estimates can be calculated using applications of the SASI model, but only if effort allocation is well understood. However, the effect of ground cable modifications on species catchability, limitations across the gradient of habitat complexity, and thus fishermen

13 profits and effort allocation, is not well understood. Any gear modification impact analysis, including its general effectiveness in terms of adverse effect mitigation, will necessitate assumptions regarding the relationship between catchability and ground cable length, and there is little data known for our region on which to base these assumptions. Past changes to fishing gears have been authorized following extensive field trials of the new gear type to determine how target and non-target species catches are affected. There is one good example of ground cable changes made in the North Pacific where habitat protection was one of the primary management objectives. Scientists and fishermen in the Bering Sea have examined the habitat and bycatch related benefits and costs to industry of ground cable changes (Rose et al. 2009, Rose et al. 2010). The wire ground cables (called sweeps in the North Pacific) were raised off the seabed by adding cookies of various sizes at various spacing intervals. They examined changes in the catch of target and incidental species and found that seafloor contact could be reduced with relatively low associated losses in catch. As of 2011, Bering Sea flatfish trawlers must use the reduced contact gear. Similar experiments in the Northeast would provide the knowledge necessary to fully gauge the net effect of gear modifications on EFH.

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15 Updated PDT Recommendations on Dedicated Habitat Research Areas NEFMC Habitat Committee August 23, 2012 Outline 1. Comparison of Before After Control Impact design with Control Impact design What results are generated with a BACI design? What are the trade offs associated with a CI design? 2. Compare alternatives for implementing fishing treatment areas What are the tradeoffs associated with the different options? 3. Considerations for determining appropriate sub area sizes 4. Recommended review timelines 5. What questions can we answer with research areas? General questions and hypotheses Review examples of previous work Distributions of managed species and habitats in three locations 1

16 Work completed since June meetings Working group meeting on July 19: BACI vs. CI design Discussed DHRAs fully inside the adverse effects areas. What do we lose in moving from BACI to essentially a CI design? Fishing treatments and tradeoffs Assessed tradeoffs associated with open fishing vs. limited access vs. research directed only fishing in the impact treatment(s). Area size Developed a list of trade offs associated with variations in DHRA treatment size. Justified the size of treatment areas and explained the need to assess multiple sizes of fishing impacts in terms of management advice. Logistics, resources, and review Identified appropriate timeline for review. More work to be done later once proposals more fully developed. Completed after the working group meeting: Specific research questions For potential research areas, describe past work; also describe distribution of managed species and habitats. PDT review of materials (1) Comparison of Before After Control Impact design with Control Impact design 2

17 BACI Area design Before After Control Impact This design will produce results that: Will separate the effects of fishing from environmental variability and species interactions. Address effects of timing (season) and size (spatial footprint) of impacts Address the potential for multiple states of recovery Identify the effects of particular types of gear and levels of effort on habitats in multiple states of recovery. Determine how fish production is affected by seafloor habitats in multiple states and different trajectories of recovery. New Closure Status: Open Closed This treatment can be accommodated in previously open areas that will be closed Open Open Fishing Control Recovery Previous Closure Status: Closed Susceptibility Closure Control Sequential closing could address temporal effects on recovery trajectories CI area design Control Impact This design will produce results that: Will separate the effects of fishing from environmental variability and species interactions. Will limit all comparisons of recovery to the single state existing within the current closed areas. Address effects of timing (season) and size (spatial footprint) of impacts Address the potential for multiple states of recovery Identify the effects of particular types of gear and levels of effort on habitats in multiple states of recovery. Determine how fish production is affected by seafloor habitats in multiple states and different trajectories of recovery. Devil is in the details Open New Closure Status: Closed Open Open? Fishing Control Recovery Previous Closure Status: Closed? Susceptibility Closure Control 3

18 Are CI style DHRAs worthwhile? Maybe The CI approach for the fishing treatment severely limits the utility of a DHRA. Furthermore, this approach would fail to take advantage of a unique opportunity to advance our knowledge of the potential benefits of closed areas (recovery dynamics, gear specific impacts and relationships to fish productivity). Another consideration Limiting DHRAs to existing adverse effects areas that focus on gravel habitats eliminates ability to assess fishing effects on habitat and productivity of species not primarily associated with hard substratum especially seasonal effects related to YOY recruitment (e.g., yellowtail flounder, silver hake, etc). From Auster et al Env Biol. Fishes 4

19 Stellwagen Region Green = newly proposed Jeffreys Ledge AE Area Purple = newly proposed Stellwagen AE Area (Both gravel habitat focused) Hatched is current WGOM habitat closure no mobile bottom tending gear Red dotted is current WGOM groundfish closure no gear capable of catching groundfish Cashes Ledge Region Pink = newly proposed Fippennies Ledge AE Area Blue = modified Cashes Habitat Closure Yellow = newly proposed Ammen Rock AE area (All gravel habitat focused) Hatched is current Cashes habitat closure no mobile bottom tending gear Red dotted is current Cashes groundfish closure no gear capable of catching groundfish 5

20 Northern Edge Region Pink = newly proposed Georges Shoal W AE Area Green = newly proposed Georges Shoal E AE Area Hatched = newly proposed ground cable modified area (All gravel habitat focused) Cross hatched is current CAII habitat closure no mobile bottom tending gear Red dotted is current CAII groundfish closure no gear capable of catching groundfish (2) Considerations for determining appropriate sub area sizes 6

21 Trade offs in Size of DHRA Treatments Overall size will depend on decisions regarding DHRA design and goals Assessing the effects of habitat impacts on fish productivity will require larger areas because of movement patterns of fishes (as compared to evaluations of how fishing effects seafloor habitats alone) Size of DHRA treatments for gear impact studies will depend on how many gear types and replicates need to be nested within each Note that recovery is in part affected by the size of the impacted area and how it is nested within unimpacted habitat Size matters! 0.5 nm? Subarea for each treatment: 1 nm? Replicate Replicate 0.5 nm? Buffer Replicate 1 nm? Replicate 0.5 nm? Replicate 0.5 nm? 1 nm? Etc. Subareas should accommodate: Multiple replicates (at least 3 per treatment) Buffers to deploy and recover fishing gear in a way that does not affect adjacent treatment areas Buffers in which treatments are nested and provide relatively equal potential for source areas to influence recovery Small/rectangular areas can be used for gear impact studies Long, linear areas can be used for studies where catch data are required 7

22 (3) Compare alternatives for implementing fishing treatment areas Fished Treatment Access Alternatives Effort type Potential benefits Potential costs Replicates an open area fishery; low administrative costs 1 Treatment gear type unrestricted; other gear types prohibited 2 Limited access; possibly additional reporting requirements 3 Scientist contracted fishing Can specify type and location of fishing ahead of time, to some extent; could get additional fishery dependent data as a requirement of the program Ensures aparticular amount and location of treatment fishing; lower administrative costs, but would require up front planning No guarantee that treatment fishing will occur; realized effort will vary over time; amount of effort could vary from year to year; fishery dependent data might not be sufficient No guarantee that treatment fishing will occur; high administrative costs to set up and monitor Highest costs to researchers and continued treatment fishing would depend on funding; difficult to replicate a commercial fishery; might be gaps in impacts if funding is limited, which could be an issue in long term impacts studies. Where would fish come from? Set aside? 8

23 (4) Recommended review timelines Timelines to Assess Progress Recommendation: A review after a minimum of 5 years to assess progress towards meeting general and site specific goals, revision of goals based on lessons learned, adverse impacts to the fishery, and future status of the DHRA. 9

24 Feedback requested What designs can we consider? Full BACI, or just CI? What type of fishing effort can be considered within treatment subareas? Open, limited access, research directed? How large an area is required for each replicate to deploy/fish/retrieve mobile gears? Fixed gears? (In other words, what is the minimum cell size needed.) Other comments? (5) What questions can we answer with research areas? General questions and hypotheses 10

25 What are the general questions? Gear impacts: Habitat recovery: Natural disturbance: Productivity: What are the effects of different gears on physical and biological habitat? Are our estimates of gear contact accurate? Can minimal contact gear be designed? Are patterns of recovery and resilience universal? What are the effects of patch size on recovery? How does the magnitude and distribution of fishing effort influence impacts? What are the dynamics of natural disturbance in contrast to fishing effects? How does the productivity of managed species (and prey) vary across habitat types? Where we are today and the need to account for role of current habitat closures Accumulated yrs of recovery (perhaps not resilience). SASI model is temporally neutral across the space domain and does not account for existing state of habitats with long recovery times inside current closed areas (i.e., hard substratum and deep mud communities) Assuming that fish production in habitat closures is solely due to reduced F, we discount the assumed link between EFH and the distribution, survival and growth of fish. Absence of evidence is not evidence of absence of effects, so we need to articulate a set of assumptions about ecological processes to move through analysis of options/alternatives. 11

26 Evidence of fish habitat relationships = use of particular habitat features, inferred and modeled links to population processes Evidence of closed area performance = recovery of seafloor communities, increased complexity and diversity (prey) sometimes others 12

27 Evidence of closed area performance = spillover from closed areas 13

28 Inference of ecological processes that can explain pattern H o No relationship to habitat state (or state of habitat recovery) and fish population response only due to mortality closure. Assumes no link between habitat (recovery) and fish abundance (life history stage) within and spillover (movement) from closed areas. No enhancement of survivorship (refuge function) No enhancement of growth reproduction (prey resource function) Inference of ecological processes that can explain pattern H a1 Habitat state (due to recovery) results in enhanced feeding opportunities, resulting in increased density, growth and fecundity. Spillover a density dependent response. Stable isotope and gut content studies indicate feeding on different faunas (linked to recovery?) inside versus outside closed areas for some species. Observations that Pandalid shrimp occur in high density patches of epifauna (Corymorpha, Cerianthid forests) and that fish feed within such patches. Match mismatch to prey availability. More? 14

29 Inference of ecological processes that can explain pattern H a2 Habitat state (due to recovery) results in enhanced survivorship 0+ to age? fish exhibit enhanced survivorship based on refuge provided by emergent benthos (from predators, flow). Potential link to enhanced growth and rapidly moving through size stanzas to reduce predation success. Requires a level of residency inside closed areas to accrue benefit. Match mismatch link to habitat availability. Hypotheses are not necessarily exclusive Dependent on: Species Life history stage Ecological setting 15

30 (5) What questions can we answer with research areas? Some examples of past closed area studies Do juvenile fishes utilize particular habitats? Acadian Redfish (Sebastes fasciatus) Photo: P. Auster and P. Donaldson, NURC, UConn 16

31 Are boulder reefs redfish pumps? Habitat Redfish size Totals Type 0-10 cm cm 21+ cm Boulder Cerianthid Totals Auster et al Silver Hake (Merluccius bilinearis) Auster et al. 1997,

32 Relationship between the size of silver hake and sand wave period Silver hake length (cm) Silver hake length (cm) Silver hake Silver hake Stellwagen Bank Sand 3 0 wave 4period Georges Bank Sand W ave Period Lab studies by Gerstner (1998) have shown an optimal relationship between fish size (cod) and sand wave period. Use of sand wave habitats can yield energetic savings in station keeping. Auster et al Sand Wave W ave Length Period (cm) Match Mismatch Hypothesis for Habitats 18

33 Habitat Recovery: WGOM/SBNMS gravel habitats in 1998 Habitat Recovery: WGOM/SBNMS gravel habitats in

34 Gravel habitat stations WGOM/SBNMS Changes in Effort and Gear Over Time Series

35 Do season, closure, and habitat influence the ecology of groundfish in the western Gulf of Maine? Atlantic cod Haddock Study Area Monkfish Jon Grabowski Hypotheses 1) Groundfish abundance will be higher inside WGOM 2) Juvenile groundfish will favor structured habitat for shelter 21

36 Site Selection and Sampling Design Factorial design (2 x 2 x 2) to test: 2 Season: Spring vs. Fall 2 Closure: In vs. Out 2 Habitat: Mud vs. edge 4 replicate sites; 3 way ANOVAs Sampled abundance, length, condition & diet Sampling conducted on 54 trawler 20 m otter trawl: 5 cm cod end with 2.5 cm liner 15 min tows at knots (mimicked methods of ME/NH Inshore Trawl Survey) 7 6 Cod Abundance Edge Mud Abundance (#/tow) Inside P-value = 0.01 Outside 22

37 Cod Length Length (mm) Spring P-value = Fall How does WGOM affect groundfish populations? Juveniles Adults Atlantic cod Juveniles & Adults on Edge in Closure; No Habitat Effect Outside Closure Haddock N/A (Did Not Catch) Adults on Edge; No Closure Effect Monkfish Juveniles Inside Closure No Habitat or Closure Effects 23

38 (5) What questions can we answer with research areas? Characterizing some of the proposed DHRA locations Stellwagen Bank habitat and species Habitat characterization: Depths less than 20 m near the coast, increasing across the bank to the northwest, w/ the flat bank top at between m. The top of the bank contains large swaths of granule pebble habitat, with areas of sand, cobble, boulder ridges, and rock outcrops. NW of the bank there is an area with very complex topography, and water depths change rapidly from as shallow as 70 m to as deep as 170 m. This area consists of boulder ridges and rock outcrops interspersed with deep mud dominated habitats. Another topographically complex area lies to the east of the bank. Similar areas of boulder ridges and rock outcrops interspersed with deep muds are expected, but the area has not been as well mapped as areas to the west. Contains both high and low energy habitats. Managed species: High rel abundance of cod, haddock, pollock, plaice, yellowtail flounder, ocean pout, and herring. High to mod rel abundance of white hake, silver hake, and redfish. Mod abundance of halibut, winter flounder, red hake, thorny skate, wolffish, monkfish, and sea scallop. Known spawning area for haddock, pollock, wolffish, and herring. 24

39 Cashes Ledge habitat and species Habitat characterization: Less than 20 m at the shallowest point, about 100 m at the edge of the ledge, adjacent deep water habitats to 200 m. Cashes Ledge is topographically complex relative to other areas being considered in the GOM, with many areas of relatively steep slopes. Contains a full range of substrate grain sizes, ranging from mud to boulder. Areas less than 20 m have dense coverage of Laminaria kelp, while areas between m have a loose canopy of shotgun kelp. Bedrock and boulder habitats without kelp coverage are found at depths of m. Waters m and deeper are dominated by mud and sand. Contains high and low energy areas. Managed species: Highly productive. High population density of cod when compared to elsewhere in the Gulf of Maine (Grabowski 2009). High to moderate relative abundance of monkfish. Moderate relative abundance of pollock, redfish, wolffish, and herring. Plaice, silver hake, and red hake moderate to rare. Ocean pout and witch flounder abundance is uncertain. Northern Edge habitat and species Habitat characterization: Rel flat and high energy. The substrate consists of long gravel formations interspersed with sand ridges. The gravel areas are dominated mainly by granule pebble and cobble grain sizes, with occasional boulder dominated areas. Along the edges of the bank, starting between 70 and 80 m, depth increases relatively rapidly. The energy regime shifts from high to low, and the substrate changes from gravel to sand dominated. At around 170 m, the slope begins to flatten out again and the energy regime is uniformly low. The substrate distribution here is mainly sand dominated, with some areas of mud. Managed species: High to mod rel abundance of cod, haddock, red hake, little skate, herring, and sea scallop. Moderate rel abundance of pollock, halibut, yellowtail, winter flounder, silver hake, white hake, barndoor skate, winter skate, ocean pout, and wolffish. Known spawning area for cod. 25