Managing Lower Trophic Level Species in the Mid-Atlantic Region

Transcription

1 Managing Lower Trophic Level Species in the Mid-Atlantic Region Forage Fish Workshop Mid-Atlantic Fishery Management Council Raleigh, orth Carolina 11 April 2013 E. D. Houde orthwest Atlantic Coastal and Shelf Ecosystems Productive Coastal Zone Major Productive Estuaries Connected to Southern ew England and Georges Bank Connected to South Atlantic shelf ecosystems Bounded by the Gulf Stream Strongly seasonal 1

2 Productivity of W Atlantic Shelf Ecosystems Primary Production Productivity on a par with Southern ew England and Georges Bank Chlorophyll a EFSC Ref Doc Candidate MA Forage Species Species Fished Retained Discarded Bycatch Bycatch Butterfish yes yes yes Atl. mackerel yes no yes Longfin squid yes yes yes Illex squid yes yes yes Atl. herring yes? yes Atl. Menhaden yes no yes River herrings no no? yes Sand lance no no no Round herring no no yes Sardines no no? Anchovies no no? Who are the Major Predators? 2

3 MAFMC SSC ESC Definition Regular info input to OFL/ ACL/ABC process EW Is this a forage stock? Stop, Apply Regular ABC Control Rules Is the stock retained in a fishery? Treat as S 1 Ecosystem Component species Is this a bycatch only fishery? Are there adequate catch (landings) data? Is there an accepted stock assessment/ w/ofls? Address in Primary fishery Are there adequate biomass data? Are stock catch (landings, or B proxies) <, =, or > PP threshold? <, = (Use B proxies) > Get data, be precautionary Increase buffer to OFL proxy Does SA consider predation at all? Mild increase to OFL buffer Are Landings (catch) stable? Does SA include predation directly (M2)? Decrease to OFL buffer Apply Regular ABC Control Rules 3

4 Probability of Overfishing 8/28/2013 Managed Forage Species Modified Council Risk Policy forage 45 typical atypical B/Bmsy Can the MAFMC Develop a Forage Policy? orth Pacific Council Ecological Considerations for Forage Groundfish FMPs have a forage category as part of the ecosystem component (EC) of the fishery (8 families and 1 order); directed federal fisheries prohibited with 2% (fish on board) bycatch cap for this EC forage group M2 (predation mortality) term incorporated in stock assessments (where possible); increasing number of multi-species assessment models being developed PDTs and SSC evaluate trends in M due to predation when setting ABC for target species (may reduce ABC below max allowed if warranted) Increased biomass thresholds for commercially-important prey species to insure adequate forage for Stellar sea lions (reduced fishing as biomass thresholds are approached); Time/area restrictions to avoid local depletion Ecosystem Considerations Report appended to groundfish and crab SAFE documents Established system O cap for BSAI (85% of sum of MSs for managed species) and GOA groundfish fisheries (95% of sum of MSs for managed species) Most recently developed Arctic FEP which includes system level cap=zero 4

5 PFMC Coastal Pelagics Species (CPS) FMP Includes Pacific sardine, chub mackerel, northern anchovy, jack mackerel, market squid, and krill (euphausids) Council banned harvest of krill in west coast EEZ (to prevent directed fishery development) in 2006 Sardine and chub mackerel are actively managed, others are monitored species PFMC: Amendment 13 (Sept 2011) to CPS FMP Modified existing harvest control rules to include ABC buffer relative to OFL through a combination of scientific advice from SSC and a policy determination of the Council (based on Council risk tolerance) Amendment 13 maintained default harvest control rules for monitored stocks (ABC equals 25% of OFL/MS) 5

6 CPS Harvest Control Rules Contain cutoff biomass reference points Cut-off is defined as biomass level below which directed fishing is prohibited Pacific sardine cutoff is 150,000 mt (or three times the overfished threshold); the control rule also contains environmental parameters to explicitly adapt harvest levels in response to environmental variability Coastal Pelagic Species: PFMC Managed Species Control Rule OFL = Biomass x F msy x Distribution ABC = Biomass x Buffer x F msy x Distribution ACL ABC General Harvest Control Rule HG = (Biomass Cutoff) x Fraction x Distribution ACT = HG or ACL, whichever is less MAXCAT also is defined The Harvest Control Rule Assures that Exploitation Rate Declines Continuously as Biomass Declines 6

7 PFMC FEP Initiative 1 Council proceeding with development of FEP Initiative 1 protection for un-fished forage species Objective is to prohibit development of new directed fisheries on forage species until Council has adequate opportunity to assess the science relating to any proposed fishery and any potential impacts to existing fisheries and communities Developed inventory of un-fished forage species and currently authorized gears and fisheries in US west coast EEZ SSC ational Workshop IV: EBFM and Forage Fish Issues eed better ways to estimate forage biomasses eed better ways to estimate predator demand Determining M2 is important Ecosystem forage buffers vs singlespecies buffers? 7

8 For consideration Indicators and reference points Are there any rules of thumb, e.g., F < M, Biomass threshold, hockey-stick (Restrepo, Lenfest) rules, appropriate F and B levels. Can predator demand be indexed from stock assessments of predators? What indices of ecosystem state are available that are indicative of predator demand and prey availability? Can energetics modeling be useful to estimate demand? What about ecosystem modeling? Strategic or tactical? What decisions and regulations could be implemented by managers in the short term? Leave one third for the birds Cury et al

9 Log 2 A (abundance) 8/28/2013 Atlantic Menhaden Chesapeake Bay Integrated Biomass Size Spectrum (combined 1997 and 1999 data) phytoplankton mesozooplankton Fish larva Zooplanktivorous small fish Piscivorous large fish 2 m 20 m 200 m 2 mm 20 mm 20 cm Organism Size 9

10 Menhaden: Allocation and EBFM Bluefish Commercial Fishery Predators/Piscivores Striped Bass Weakfish Osprey What is a Fair Allocation Plan? Can Humans Cause Localized Depletion? Recreational Striped Bass Fishing 10