Gulf of Mexico Red snapper

A Review of the SEDAR Stock Assessment of Gulf of Mexico Red Snapper (and some ways it might be improved) Southeast Fisheries Science Center

Clay Porch (with Shannon Calay and a lot of other folks) Red Snapper Workshop March 2-3, 2016 Hilton New Orleans Riverside

Duane Raver, Jr

Outline Historical Perspective Fisheries Assessments

SEDAR assessment Information used Structural assumptions Population Estimates Reference Points and Stock Status

Unresolved Issues Possible Solutions U.S. Department of Commerce | National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 2

The Fishery: Landings

U.S. Department of Commerce | National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 3

The Fishery: Landings Photo credit: Scott Hickman

The Fishery: Discards

MT

NOAA Fisheries

NOAA Fisheries

The Fishery: Total removals

Stock assessments: a history of overfishing 1880s: “It is probable that this species is being more or less rapidly depleted” (Collins, 1885) 1950s: Most of the snapper banks off Florida considered impoverished (Camber, 1955) 1970s: Catch rates in LA/TX decline by more than 50% 1980s: 2 assessments indicate overfishing (Nelson and Manooch, 1982; Parrack and McClellan, 1985). 1990s: 5 assessments indicate stock overfished and overfishing 2004, 2009 (SEDAR 7): indicates stock overfished and overfishing, some signs of rebuilding 2012, 2014 (SEDAR 31): stock overfished, but rebuilding rapidly U.S. Department of Commerce | National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 7

SEDAR 31 and 2014 Stock definition Life History information • • • •

Natural mortality Age and growth Reproduction Conversion factors

Fishery Data Fishery Independent Data

Red snapper trail of documents (Courtesy Kenny Rose)


Stock Definition • Genetic results indicate that red snapper exhibit independent demographic assemblages on small spatial scales and support findings for a metapopulation stock-structure. • Recent larval drift study suggests east and west largely selfrecruiting • Otolith chemistry suggest low connectivity between MX and TX • Tagging data suggest relatively little movement across Mississippi river outfall area

Natural Mortality

Growth

Reproduction NOAA Fisheries

Fisheries Data (natural and artificial habitat) Landings, Discards, Effort, CPUE, Age • Com Handline • Com Longline • Rec Private Boat + Charter Boat • Headboat • Com Closed Season • Rec Closed Season • Shrimp Bycatch

Fisheries Data: Landings Age Composition Recreational: Gulf-FIN

Commercial: Trip Interview Program

Fisheries Data: Discard Age Composition Recreational: Headboat observer

Commercial: Reef-fish observer

Shrimp bycatch

NOAA Fisheries

Indices of Abundance: Fishery Dependent • Commercial Handline Indices West

East


Indices of Abundance: Fishery Dependent • Recreational: MRIP Charter + Private West

East


Fisheries-independent Data CPUE, Age composition • • • • •

SEAMAP Video SEAMAP Plankton SEAMAP Summer and Fall Trawl NMFS bottom longline Artificial Reef ROV

Indices of Abundance: Fishery Independent • NMFS Bottom Longline West

East


Indices of Abundance: Fishery Independent • Larval Survey: Used to Index SSB http://fl.biology.usgs.gov

West

East


Indices of Abundance: Recruits (Age 0 and 1) • Fall Groundfish Survey West

East


ROV/Camera surveys of artificial reefs • U. West Florida surveys (Patterson et al. 2009) • Dauphin Island Sea Lab (DISL) surveys • Panama City NMFS and FWRI ROV/Fixed Camera studies

SEDAR 31 and 2014 Assessment Model Population Estimates Stock Status


SEDAR 31 and 2014 Update: Model Structure • • • • • •

Stock Synthesis Age structured model: ages 0 to 20+, 1872-2013 2 region model : East and West of the Mississippi River Time-varying recruitment – higher productivity in recent years (1984-2013) Time-varying selectivity to account for implementation of IFQ program and circle hooks Time-varying retention to account for changes in size limits and IFQ Time-varying discard mortality to account for venting Fishing fleets

Directed fleets (landings and discards) • Com Handline (E: 1872-2013) (W: 1872-2013) • Com Longline E/W (1980-2013) • MRFSS/MRIP E/W (1950-2013) • Headboat E/W (1950-2013) Bycatch fleets (discards only) • Com Closed Season E/W (1991-2006) • Rec Closed Season E/W (1997-2013) • Shrimp Bycatch E/W (1950-2013) (1946-2013)

Indices of abundance (18) Fishery dependent (8) • Commercial Handline E/W (1990-2006) • MRFSS/MRIP E/W (1981-2013) • Headboat E/W (1986-2013) • Shrimp Fishing Effort E/W (1950-2013) Fishery independent (10) • SEAMAP Video E/W (1993-2013) • SEAMAP Plankton E/W (1987-2012) • SEAMAP Summer Groundfish E/W (1982-2013) • SEAMAP Fall Groundfish Trawl E/W (1972-2013) • NFMS bottom longline E/W (1986-2013)

Number of Red Snapper in Population Millions

Number of Fish

Age 2+ Red Snapper in Eastern GOM 18 16 14 12 10 8 6 4 2 0 1980

1990

2000

2010

Age 2+ Red Snapper in Western GOM

Number of Fish Millions

35 30 25 20 15 10 5 0 1980

1990

2000

2010


Fraction of Red Snapper Removed by Fishing

Declines to 10-14% after 2007 ~30% 20002006


Fraction Age 3+ Doubles to 6-9% after 2007

~3% 2000-2006


Spawners (egg production) West East

NOAA Fisheries


Recruitment West East

www.ag.auburn.edu


Little relationship between spawners and subsequent recruitment SSC adopted a proxy for MSY of 26% SPR


Reference points for Gulf of Mexico Red Snapper Global Maximum Yield Per Recruit

Yield with current mix of fisheries at maximum yield per recruit Yield with current mix of fisheries at 26% SPR

2 Source: Matthew Smith and Dan Goethel

*Recruitment assumed to remain near Oceanic recentand levels, therefore MSY| =NOAA longterm U.S. Department of Commerce | National Atmospheric Administration FisheriesYield | Pageat 32FMAX

Gulf of Mexico Red snapper: SPR at MSY SPR at global MSY

SPR with current mix of fisheries

Source: Matthew Smith and Dan Goethel U.S. Department of Commerce | National Oceanic and Atmospheric Administration | NOAA Fisheries | Page 33

Spawning Potential Ratio: Project F Rebuild 2000-2006: 18% increase in SPR 2006-2014: 220% increase in SPR

Rebuilds to 26% in 2032

15.8% in 2015

~4.5 % 2000-2006


Towards improving the assessment Historical Landings Recreational discards Affects estimates of abundance and effect of fishing Release mortality Natural mortality rate Affects perception of Spawner-recruit relationship stock productivity Habitat changes (artificial reefs etc.) Stock structure


Historical landings and recreational discards Affects historical perception of abundance (N) and fraction of population removed by fishing (F) • The stock assessment essentially estimates N and F from the amount of change in the density of fish D after the catch C is removed • If D or C are uncertain, then N and F will be uncertain • Alternative is to estimate N and F more directly • Survey for absolute abundance of fish over entire domain (advanced technology) • Mark-recapture experiments

Natural mortality rate (M) Affects historical perception of N and F as well as expectations of future productivity/sustainability • The stock assessment assumes an average value of M that is based on maximum age of red snapper (50+ years) and does not vary through time Scale of M could be estimated in a single year study via markrecapture experiments

• M may in fact change through time and could be density dependent Density dependence requires multiple years of process study with strong contrasts in abundance

Spawner-recruit relationship Affects expectations of future productivity • Assessment suggests that recruitment was higher over the last few decades than in the past despite apparent declines in total egg production (assumes this level of recruitment will continue into near future) o Change in environment (Mississippi outfall, etc...) o Episodic contributions from Mexico o Increased juvenile survival owing to artificial reefs and shrimp trawling, density dependent juvenile survival

• True nature requires good data measured over a wide range of egg production levels

Stock structure Affects expectations of future productivity • Improved local management • Extirpation of one stock results in overall decrease in productivity (and genetic diversity) • Genetic / microchemistry sampling • Mark-recapture studies (stock movements) • Conventional / electronic for short-term • Genetic for longer term (samples can be collected simultaneous with conventional program, but some time needed for marker development)

Contribution of artificial reefs Clearly make red snapper easier to catch, but do they increase production? • Higher density on artificial habitats, but much more natural habitat o If total population on artificial reefs is small compared to natural reefs, then production probably also small o Otherwise, need process studies (or really long time series with contrast in # reefs)

• Improved maps of artificial and natural structures combined with abundance surveys (advanced tech?) • More process studies

The Challenge of Scale

Example: Alabama visual survey  A large fraction of age 3-8 eastern Gulf

Red Snapper are off Alabama (30-50%)

Relative frequency

0.25 0.2

Sedar 31 Eastern Gulf Estimate (3-8 year olds)

0.15 0.1 0.05 0 0

5,000,000

10,000,000 15,000,000 Red Snapper (#)

20,000,000

Powers, S. 2014. Red Snapper Population estimates in Alabama’s Reef Permit Zone. GMFMC Presentation September 2014

The Challenge of Scale NMFS bottom longline survey sets (prior to 2010)

Powers study area (Alabama)

The Challenge of Scale Representative sampling over the entire domain. A pipe dream?

The Challenge of Scale

Example: Potential acoustic arrays May be less of a pipe dream? Mississippi River (eastern/western Gulf) Cape San Blas

Mid-Atlantic and South Atlantic Council borders Cape Canaveral

Gulf of Mexico and South Atlantic Council borders

U.S. / Mexico border

Gulf and Caribbean

Primary locations at jurisdictional boundaries and Mississippi River Secondary locations at other perceived biogeographical barriers

The Opportunity for Partnerships

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