A Bioeconomic Model of the Recreational Gulf of Maine Cod and Haddock Fishery

Transcription

1 A Bioeconomic Model of the Recreational Gulf of Maine Cod and Haddock Fishery Min-Yang Lee 1, Scott Steinback 1, and Kristy Wallmo 2 1 NOAA Fisheries, Northeast Fisheries Science Center, Woods Hole, MA 2 NOAA Fisheries, Office of Science and Technology, Silver Spring, MD

2 Research/Policy Questions How do changes in management measures affect recreational anglers who are targeting cod and haddock in the Gulf of Maine? Size limits Possession limits What combination of management measures can achieve conservation objectives? How do these changes affect stock sizes?

3 Outline Economic sub-model Behavioral model of anglers 29 choice experiment survey Biological sub-model Some preliminary results Future research

4 Model Overview Biological Sub-Model Economic Sub-Model Encounters of fish Length Structure Estimate a behavioral model for recreational anglers Simulate Fishing for a Year Effort Welfare Discards Aggregate and Project stocks of fish Retained

5 Economic Sub Model Groundfish Choice Experiment Survey Add-on to NMFS MRFSS Survey in 29 (ME-NJ) Voluntary mail follow-up Dillman surveying approach Economic Sub-Model

6 Groundfish Choice Experiment Survey Five Components Description of study A species information page Screener questions familiarity and avidity CE questions Demographic questions Economic Sub-Model

7 8x per survey SECTON B: SALTWATER FSHNG TRPS Please compare Trip A, Trip B, and Trip C in the table below, then answer questions 1 and 2. Compare only the trips on this page. Do not compare these trips to trips on other pages in this survey. Assume that the trips below are identical in every way except for the features listed in the table. All regulations remain as they are today unless otherwise noted in the table below. TRP FEATURES TRP A TRP B TRP C Vary these attributes TRP DETALS CATCH REGULATONS DALY BAG (TAKE) LMT Number of fish you can legally keep per day. MNMUM SZE LMT Smallest fish you can legally keep of this species. NUMBER OF LEGAL-SZE FSH YOU CATCH These fish are at least legal minimum size. Some fish are released if you catch more than the daily bag limit. NUMBER OF UNDERSZED FSH YOU CATCH These fish are below the legal minimum size. All of these fish must be released. NUMBER OF OTHER FSH YOU KEEP Other fish you catch on this trip that can be legally kept. TRP LENGTH Total time purchased for this trip. TOTAL TRP COST YOUR share of the fishing trip cost, including bait, ice, fishing equipment, daily license fees, boat rental fees, boat fuel, and round trip transportation costs associated with traveling to and from the fishing location. Travel costs may include vehicle fuel, car rental, tolls, airfare, and parking. This cost does not include the price of food or drink. 4 Pollock 1 Cod 23 inch Pollock 22 inch Cod 1 Pollock 1 Cod 1 Pollock 3 Cod 3 Cod 6 Haddock 1 Haddock 3 Pollock 8 Hours 12 Hours $312 $276 Do something other than saltwater fishing. 1 like this trip best: (Please mark the ONE option YOU like best with a or ) TRP A TRP B TRP C 2 Please rate the trips listed in the table above. (Circle the number that reflects your opinion best.) TRP A DSLKE LKE TRP B DSLKE LKE TRP C DSLKE LKE Questions? Call Sonia Jarvis at x14 or Sonia.Jarvis@NOAA.GOV 4 Economic Sub-Model

8 Attributes and Levels in CE Attribute Bag limits 2, 4, 8, 1 Size limits: Level Many Possible Combinations Cod Haddock 18, 2, 22, 23, 24, 26 12, 16, 17, 19, 21, 22 Pollock Number of legal sized fish 1, 3, 6, 1 Number of undersized fish 1, 3, 6 17, 19, 2, 21, 23, 26 Number of other fish 1, 3, 6, 1 Trip length (hours) 2, 4, 6, 8, 1, 12 Shore mode trip cost ($/trip) $15, $35, $6, $9, $12, $15 All other modes trip cost: Hourly trip cost ($/hr.) $15, $35, $6, $9 Experimental design literature (Kuhfeld) 26 Unique Surveys D-efficiency Score ~73 Total trip cost ($/trip=$/hr. x # hrs.) $3 $18 Economic Sub-Model

9 Response Rates by State and Residency ntercept State Mailed Resident Completed Nonresident Completed Total Completed Completion Rate Maine % Massachusetts % New Hampshire % New Jersey % New York % Connecticut % Rhode sland % Total 4, ,491 33% Economic Sub-Model

10 Behavioral Model ndirectly affected by bag and size limits Economic Sub-Model

11 Behavioral Model Parameters Parameter Estimate Standard Error t value Pr >t,/ cod kept <.1,l cod released <.1,l haddock kept <.1,l haddock released Trip length x For-hire (Trip length) 2 x For-hire Trip cost <.1 Opt-out Likelihood Ratio No. Obs No. Cases {J ep 1 (. NOAA FSHERES U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 11

12 Behavioral Model Summary Model estimates how changes in expectations (mainly the number of fish kept and released) affects the value of a fishing trip But what changes expectations about kept and released fish? Regulations, stock composition, other factors Economic Sub-Model

13 Behavioral Model Limitations No explicit link between changes in regulations and expected catch in behavioral model No consideration of biological stock structures Results are not explicitly linked to changes in numbers of trips per season (i.e., effort shifts) U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 13

14 Model Overview Biological Sub-Model Economic Sub-Model Encounters of fish on a trip are function of catchability and skill Fish kept are a function of length structure, selectivity, regulations Behavioral Model Effort Welfare Simulate angler behavior under alternative stock structures and regulations Discards Aggregate and Project stocks of fish Retained

15 Bioeconomic Model Simulate a year of fishing effort at the trip level using: The estimated behavioral parameters Historical encounter (catch) rates Stock structures Length-based targeting of fish U.S. Department of Commerce National Oceanic and Atmospheric Administration NOAA Fisheries Page 15

16 Encounters of Fish Encounters of fish on a trip are a product of many angler and trip attributes which are not observed. ndividual attributes: Skill and familiarity Trip attributes: Mode, location, weather, time spent, time of year, bait, gear Luck Availability of fish Biological Sub-Model

17 Encounters of Cod and Haddock The distribution of Encounters-per-trip derived from MRFSS (27-29) Encounters=Kept+ Discard Lots of zeros Approx 25% of trips do not encounter a cod Nearly 6% of trips do not encounter a haddock

18 Catch-at-Length What is the length-distribution for fish which are caught by recreational anglers? Not the same as: Length distribution of stock Pair with bag, size limits to determine how many fish are kept and released. Doesn t account for targeting behavior Length distribution of historical catch Doesn t account for changing stock conditions 18

19 Combining Stock Assessment and Recreational Catch data Age-Length Data (Survey) + Historical Numbers at Age (Assessments) Historical Recreational Selectivity-at-length Historical Catch-at- Length (MRFSS) + Historical Numbers at Length Current Recreational Selectivity-at-length Life History, Commercial Fishing (F), other parameters Current (213) Numbers at Age (Projected) Recreational CPUE-at-length

20 Numbers-at-Age and Age-Length GoM Cod Numbers-at-length GoM Cod Age-Length Relationship

21 Cod Recreational Catch Recreational Selectivity "<t C') C\J Length (in) Raw Recreational Catch --- Smoothed Recreational Catch ~..., c::: Q) _J iii (/) mg.oo Eo ::::1 z1 " (.) / / ~-, : ' \ ~, : \~ \ ', \ \ \ \., /,,... ~ ,, ~ Length (inches) Cod Mean Numbers-at-Length Recreational Cod Selectivity 4 5 (. NOAA FSHERES Not in the document

22 Catch-at-Length for Median 213 GoM Cod Stock... L() T""" -co :::::lt""" () ~ Oo L() /..., \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ co C\J LENGTH Cod projected 213 Numbers-at-Length Probability distribution of recreational catch-at-length (. NOAA FSHERES

23 Catch-at-Length for Median 213 GoM Haddock Stock... <. c ::J Oo.:: (.) " ~ -g o C\J.; _., / / / / /' ' ' \ \ \ \ \ \ \ \ \ \ \ \ J \ \ C\J :.a T"""«j.. LO e a LENGTH Haddock projected 21 3 Numbers-at-Length Probability distribution of recreational catch-at-length 3 (. NOAA FSHERES

24 Simulating Expected Catch for a Trip Draw the number of encounters Draw Length of A Fish Recreational Catchat-Length Yes Greater Than Minimum Size? No No Reached Possession Limit? Add to Bag Discard Yes Reached Encounter Limit? Yes Stop Fishing No Compute Expected Catch

25 The Participation Decision Expected Catch WTP For a Trip Other Trip characteristics Behavioral Model Coefficients Probability a Prospective Trip Will Occur < 5% >5% Behavioral Model Coefficients Trip Occurs Trip Does not Occur Simulate Actual Catch

26 Simulating Actual Catch for a Trip Draw an Encounter limit Draw Length of A Fish Recreational Catchat-Length Yes Greater Than Minimum Size? No No Reached Possession Limit? Add to Bag Discard Yes Reached Encounter Limit? Yes Stop Fishing No Compute Actual Catch

27 Simulating the Entire Recreational Fishery How many trips will occur? Set a number for potential trips Large enough so that this number is not binding if the fishery becomes more desirable Cutoff probability from behavioral model (5%)

28 Calibration Use possession and size limits in effect for Set number of potential trips so that Trips matches actual trips. MRFSS Average Model Predictions Potential Trips N/A 465, Error Trips 283,41 284,228.3% Cod Kept 419,971 33, % Cod Released 1,27,738 1,53, % Total Cod 1,447,79 1,357, % Haddock Kept 356,99 355, % Haddock Released 96,359 22, % Total Haddock 452, , %

29 Policy Analysis Examine illustrative changes in bag and size limits 5, 7, 1 fish for cod 18, 2, 22, 24, 26 inches for cod ncorporate variability regarding stock conditions

30 Policy Analysis Project a sample of age classes for both species Select a bag and size limit combination Randomly select a 213 starting stock Simulate a year of fishing under that policy Repeat for all combinations of bag & size limits Repeat 2x Save the outputs: WTP, effort, catch, discards

31 Results numbers of kept cod Possession limit Size limit

32 Outcomes of some policies are very sensitive to discard mortality 5,, Cod Removals (Kept + Dead Released in pounds) 4,5, 4,, 3,5, 3,, 2,5, 2,, 1,5, 1,, 5, Discard Mortality Rate (%) 1 Fish, 18" Minimum 7 Fish, 18" Minimum 7 Fish, 26" Minimum

33 Acknowledgements Liz Brooks, Paul Nitschke, Mark Terciero, Chris Legault NEFSC Population Dynamics Branch Sonia Jarvis, Doug Lipton, Ted McConnell, University of Maryland Dan Georgianna, University of Massachusetts-Dartmouth Cynthia Jones, Old Dominion Eric Thunberg, NOAA Fisheries Office of Science and Technology

34 Assumptions No changes in catchability/targeting behavior Catch-at-length determined by catchability and relative abundances of length classes Expectations correctly generated: Anglers generate expected catch based on length of fish in water and catchability. Note: Expected catch for trips which occur is generally higher than actual catch.

35 Assumptions cont d No heterogeneity in catch rates across fishing modes, time, or space No recreational high-grading Anglers stop fishing for either species when they hit the maximum or the bag limit No illegal retention* (too small, over bag limit)