Engineering Bycatch Reduction in West Indian Fish Traps: STFA CRP Trap Vent Study CRP Project No. NMF

Prior Escape Vent Studies Source Vent Height (inches) Vent Width (inches) Trap Mesh Size Fish/ Trap Haul (Control Traps) Munro (1999) inch Johnson (2010) inch / STFA Pilot (2008) 612 Inch STFA CRP (2010) 61 3/4 2 Inch /4 1 1/2 5 3/ /4 1 3/8 9 3/4 1 3/8 5 3/4 1 1/4 Olsen, Dammann and Laplace (1978) 1 inch by 2 inch Inch1.8

1 by 16 inch Edge 1 by 5 3/4 inch Vent 1.5 by 5 3/4 inch Vent 1 3/4 by 5 ¾ inch Vent 1 3/8 by 9 3/4 inch Vent 1 3/8 by 5 3/4 inch Vent 1 3/8 by 5 3/4 inch Vent Escape Vents Tested

Summary of Trap Hauls Diving StudiesField Testing Vent Type Initial Dive Initial Haul Trap Stock- ing Phase 1 Phase 2 Phase 3 Phase 4 Control by 5 3/4 Vent in Edge /2 by 5 3/4 Vent /4 by 5 3/4 Vent /8 by 5 3/4 Vent * 1 3/8 by 9 3/4 Vent Total * Located top and bottom front and back of the traps.

Video Studies 24 hour videos from 8 days (Renchen, 2010) Only daylight hours were used in order to be able to identify fish species and positions.* Position of fish in trap recorded every 5 minutes. In vent position study, 9 vents were placed in two strings of 10 baited traps. Vents were closed following final daily observations. Each trap was observed for 20 minutes and all escapes recorded. Video was recorded for one trap each day. Renchen reported that peak ingress/egress was around noon and occurred almost entirely during daylight hours.

Video Studies

Video Summary Results

St. Thomas St. John

Vent Choice Results A total of 28 escapes were observed or caught on video. Most escapement involved back vents (74%). Most escapement involved upper vents (70%). Results were used to guide design of Phase 4 field testing.

Experimental Design (Diving Studies) 1.Each trap string inspected by diving (species counts). 2.Estimate fish required for stocking. 3.Haul non-experimental traps to collect fish necessary to supplement for stocking. 4.Haul experimental traps, measure (TL) all fish and examine for fin clips. 5.Stock traps with fish from experimental and non- experimental traps that have been fin clipped. 6.Traps set for 1, 3, 5, 7 days before being revisited.

Changes in Numbers During Trap Hauling (Initial Dive vs Initial Haul) % of Trap Hauls

Species Escapement During Hauling (Most Common Species) Species Name Initial Dive Escaped During Initial Haul % Escape BUTTERFLYFISH,BANDED % PORGY,SAUCEREYE % GRUNT,BLUE STRIPED % PARROTFISH,STOPLIGHT % BLUE TANG % COWFISH,HONEYCOMB % SCHOOL MASTER % COWFISH,SCRAWLED % DOCTORFISH 9 111% HIND,RED 57 59% GRUNT,WHITE 51 48% TRIGGERFISH,QUEEN 16 16% LOBSTER,CARIB. SPINY 38 13% TRUNKFISH,SMOOTH 32 13% ANGELFISH,GRAY 29 13% TRUNKFISH,SPOTTED 19 -0% PORGY,PLUMA 14 -0% ANGELFISH,QUEEN 10 -0% Total for all species %

Retention of Fin Clipped Fish

Retention of Fin Clipped Fish in Trap Retention of Fin Clipped Fish in Trap Hauls

Summary Larger fish were found in in longer sets (p<.06) 40-80% of the stocked fish left during the first day. Highest escapement was in traps with the widest vents. For all vent sizes most (90-100%) of the stocked fish were gone within 7 days. Larger vents sizes had faster exit rates. No species-specific tendencies were observed in exit although the larger vent sizes exhibited significant changes in species composition at all set lengths.

Experimental Design Standard St. Thomas Fish Traps – Rectangular and Arrowhead Design. – Set in Strings of 10 – Fishermen told to “fish them like they normally do” during field testing. Vents (2 per trap on the away from the funnel “front” side) – Control (no vent) – 1 by 5 3/4 inch vent – 1 inch vent along entire (18 inch) edge of trap – 1 1/4 by 5 3/4 inch Vent – 1 1/4 by 9 3/4 inch Vent – 1 3/8 by 5 3/4 inch Vent – 1 1/2 by 5 3/4 inch Vent – 1 3/4 by 5 3/4 inch Vent – Vents in Random order on trap string

Field Testing Series 1.Phase 1 field testing with vents from diving studies. 2.Phase 2 Field testing. 1 by 5 3/4, 1 3/8 by 5 3/4, 1 3/8 by 9 3/4, 1 1/2 by 5 3/4 and control traps. 3.Phase 3 testing. 1 by 5 3/4, 1 3/8 by 5 3/4, 1 1/4 by 5 3/4 (top of trap), 1 1/4 by 5 3/4 (bottom of trap) and control traps. 4.Phase 4 testing. 1 3/8 by 5 3/4 placed on the front and back top and bottom to test for vent location.

Study Catch Characterization (94 species) Category# Caught% Commercial Catch8, % Bycatch5, % Ciguatera % Non Commercial1462.8% Regulatory230.5% Too Small4, % Boxfish2, % Not Boxfish1, %

Field Testing Summary Results: General – Average Catch/Trap Haul does not stabilize until > 40 trap hauls. – No difference between rectangular and arrowhead traps – Catch/trap haul not correlated with set length. – Catch/trap haul not correlated with temperature. – Lunar affects (catches greater and fewer empty traps around full moon). – Seasonal peaks for most species. – Lionfish from 0 to 19 th most common species at end of study. – Mortality rate (0.031fish/day ) similar to diving studies and Renchen (2010) study (0.025fish/day ).

Cumulative Average # Fish/Trap Haul (Control Traps)

Species Seasonality of CPUE

Gear Selectivity

Selectivity Analysis: Fish Traps

Summary of Fish Life History Results Sample Size Species Measure- ment L first reproduction Female L first reproduction Male (mm) Min Catch (mm) MidPoint Overlap Min Catch and Max By catch (mm) % Above L first repro- duction Average Size Retained as Catch Size at 50% Recruit- ment to Fishing Gear Size at Full Recruit- ment 57Pomacanthus paruTL % Pomacanthus arcuatusTL % Holacanthus ciliarisTL Acanthurus coeruleusFL % Chaetodon striatusTL133100% Epinephelus fulvusTL Lactophrys poligoniusTL Lactophrys quadricornus TL % Acanthurus chirurgusFL % Haemulon sciurusFL % Haemulon carbonarium FL Haemulon flavolineatum FL % Haemulon plumieriFL %

Sample Size Species Measure- ment L first reproduction Female L first reproduction Male (mm) Min Catch (mm) MidPoint Overlap Min Catch and Max By catch (mm) % Above L first repro- duction Average Size Retained as Catch Size at 50% Recruit- ment to Fishing Gear Size at Full Recruit- ment 1078 Epinephelus guttatus TL % Pterois volitansTL Sparisoma chrysopterum FL Sparisoma virideFL % Calamus calamusFL Lutjanus apodusFL Lutjanus buccanella FL % Lutjanus synagrisFL % Lutjanus analisFL % Ocyurus chrysurus FL TrapsFL % HandlineFL 21092% SeineFL 20096% Panulirus argusCL Holocentrus rufusFL % Balistes vetulaTL % Lactrophry triqueter TL Lactrophrys bicaudalis TL Summary of Fish Life History Results

Total Mortality Rate The annual total mortality rate (shown in equation 5

Species Mortality Values Species# L max TL (in mm) Information from FISHBASE Current Analysis k LocationTotal Z Epinephelus cruentatus USVI1.025 Lutjanus synagris Puerto Rico0.956 Sparisoma chrysopterum BVI1.988 Sparisoma viridae USVI0.567 Lutjanus apodus USVI0.351 Haemulon Sciurus Puerto Rico0.543 Acanthurus chirurgus USVI0.517 Haemulon plumieri Puerto Rico2.727 Epinephelus guttatus1, St. John1.037 Balistes vetula1, USVI0.966 Acanthurus coerulus2, USVI0.374 Ocyurus chrusurus (Handline)1, Puerto Rico0.120 Ocyurus chrusurus (Traps) Puerto Rico0.093 Panulirus argus1, St. John0.472

Field Testing Summary Results: Vents Box fish. Only 2 by 4 and 1 3/4 by 5 3/4 vents let out boxfish and these also had very low retention of commercial catch. Study then concentrated on release of thin bodied not-box fish (TBNBF). Vent height. – 1 inch by 18 had significant release of TBNBF and retention of commercial species. – 1 by 4 released significantly less TBNBF than 1 by 6 in pilot study. – 1 3/8 by 9 3/4 Vent did not release more TBNBF than 1 3/8 by 5 3/4. Vent Width. 1 1/4 by 5 3/4 and 1 3/8 by 5 3/4 both has good release of TBNBF and retention of catch but 1 3/8 by 5 3/4 had better release of bycatch. Vent Location. Top and bottom not significant but vents in front (away from funnel) side had significantly higher release rates. (Contrasts with diving observations).

Impact of Selected Vents Control1 3/8 VentsComparison SpeciesCountAvg. TL CountAvg. TL Control CPUE Vent CPUE Reduction % Reduc- tion Control CPUE % Control TL Acanthurus coeruleus %103.8% Acanthurus chirurgus %102.9% Balistes vetula %103.3% Calamus calamus %104.6% Pomacanthus arcuatus %116.7% Holacanthus ciliaris %87.5% Holacanthus tricolor %100.4% Chaetodon striatus %101.2% Sparisoma chrysopterum %101.1% Sparisoma viride %105.1% Lutjanus apodus %100.8% Holocentrus rufus %100.7% Lutjanus synagris %100.6% Lutjanus buccanella %109.7% Ocyurus chrysurus %104.8% Haemulon plumieri %100.6% Haemulon sciurus %99.6% Epinephelus fulvus %97.8% Epinephelus guttatus %101.2% Pterois volitans %105.4% Haemulon melanurum %95.7% Lactophrys quadricornis %96.6% Lactophrys triqueter %100.3% Lactophrys bicaudalis %97.5% Lactophrys poligonius %98.0%

Impacts of 1 3/8 Vents on Selected Species Species L first repro- duction Female L first repro- duction Male Size at 50% Recruit- ment to Gear Min Catch % Above L first repro- duction % Reduct- ion from Control CPUE % Increase in TL Acanthurus coeruleus %81%4% Acanthurus chirurgus %45%3% Sparisoma chrysopterum %1% Sparisoma viride %20%5% Pomacanthus arcuatus %38%17% Holacanthus ciliaris %1% Chaetodon striatus %1% Calamus calamus %5% Balistes vetula %30%3%

Implementation Fishermen from Phase 4 of study are leaving vents in. (Julian Magras, Daryl Bryan, Tony Blanchard and Danny Berry) Proposal to Bycatch Reduction Program. – Fishermen install vents in one string. – Port Sample vent string and one regular string. – If convinced project to supply vents for remainder of traps. Council/Territorial Regulation.