Captures of protected species in New Zealand recreational fisheries - - PowerPoint PPT Presentation

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Captures of protected species in New Zealand recreational fisheries - - PowerPoint PPT Presentation

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Captures of protected species in New Zealand recreational fisheries Edward Abraham 25 June 2020 Department of Conservation Project BCBC2019-07a This presentation is of provisional work, final results may differ. Introduction This presentation

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SLIDE 1

Captures of protected species in New Zealand recreational fisheries

Edward Abraham 25 June 2020

Department of Conservation Project BCBC2019-07a

This presentation is of provisional work, final results may differ.

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Introduction

This presentation is of provisional work, final results may differ.

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Protected species

Introduction

  • All seabirds (apart from black-backed gull)
  • All marine mammals
  • All marine reptiles
  • Some sharks (including great white shark)
  • Some fish (spotted black grouper, giant grouper)
  • Some corals (including black corals)

This presentation is of provisional work, final results may differ.

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How we know about recreational fishing

Introduction

  • Boat ramp surveys have been conducted by NIWA for MPI.

Fishers are asked about their catch as they return to the ramps

  • Aerial surveys allow total fishing effort to be estimated
  • The National Panel Survey (NPS) asks fishers about their

fishing throughout the year

  • Charter fishers provide statutory returns to MPI

This presentation is of provisional work, final results may differ.

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SLIDE 5

Available data on protected species

Introduction FMA effort Spatial effort Seabird groups Seabird species Mammals Reptiles Sharks & rays Other fish Corals Charter fishing

MPI MPI Charter Charter

Boat-based line fishing

NPS NPS/Aerial Boat ramp

Shore fishing

NPS NPS

Set net fishing

NPS NPS

Other fishing

NPS NPS This presentation is of provisional work, final results may differ.

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Sources of unstructured data

Introduction

  • Bird banding database
  • Marine mammal stranding database
  • Birds New Zealand beach patrol database
  • DOC hotline
  • Shark sightings

This presentation is of provisional work, final results may differ.

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SLIDE 10

Previous boat ramp study of seabird captures

Introduction

  • 763 boatramp interviews carried out during 2007–08
  • 47% of fishers recalled witnessing a bird being caught at some

stage in the past

  • There were 21 seabirds reported caught on the day of the

interview (0.22 captures per 100 hours of fishing)

  • From this rate, there were estimated to be 11 500 (95% c.i.:

6600 to 17 200) bird captures per year in FMA 1

  • Three of the 21 captured birds were reported to have died

This presentation is of provisional work, final results may differ.

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SLIDE 11

Seabird captures on charter vessels

Introduction

  • Observers on 57 charter trips during 2007–08 recorded

seabird captures

  • A capture rate of 0.36 (95% c.i.: 0.09 to 0.66) birds per 100

fisher hours was recorded

This presentation is of provisional work, final results may differ.

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SLIDE 12

Boat ramp survey

This presentation is of provisional work, final results may differ.

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SLIDE 13

“Did you catch any birds with your fishing gear today?”

Boat ramp survey

  • Carried out between October 2017 and September 2018 by

NIWA, for MPI

  • A total of 51 295 fishers were interviewed as they returned to

boat ramps

  • Primary goal in FMA 1 was the estimation of the recreational

take of key fish species

  • Conducted along with an aerial survey
  • For the first time, fishers were asked about seabird captures

This presentation is of provisional work, final results may differ.

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SLIDE 14

Fishers asked about seabird captures, by FMA

Boat ramp survey FMA Fishers Fishing hours Captures Capture rate 1 33 537 120 566 420 0.35 2 1 818 8 085 8 0.10 3 1 999 6 830 7 0.10 5 574 1 227 3 0.24 7 2 789 8 502 5 0.06 8 1 509 5 190 12 0.23 9 1 420 4 728 0.00 All 43 646 155 130 455 0.29

The capture rate is the number of seabirds caught per 100 hours of fishing This presentation is of provisional work, final results may differ.

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Largely rod and line fishing

Boat ramp survey Method Fishers Fishing hours Captures Capture rate Rod and bait 33 536 122 041 390 0.32 Rod and lure 3 937 12 946 41 0.32 Trolling 2 121 9 340 23 0.25 Longline 802 2 000 1 0.05 Diving 2 225 4 156 0.00 Bottom gear 684 3 838 0.00 Net 186 524 0.00 Bottom line 29 124 0.00 Gathering 103 102 0.00 Mixed 10 36 0.00 Shore fishing 13 22 0.00 All 43 646 155 130 455 0.29

This presentation is of provisional work, final results may differ.

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1 2 3 5 7 8 9 46°S 44°S 42°S 40°S 38°S 36°S 34°S 166°E 168°E 170°E 172°E 174°E 176°E 178°E 180°

Longitude Latitude Captures per 100 hours

Less than 0.1 0.1 to 0.2 0.2 to 0.5 0.5 to 1.0 More than 1.0

Number of interviews

10 30 100 300 1000 3000

This presentation is of provisional work, final results may differ.

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Largely snapper fishing

Boat ramp survey Method Fishers Fishing hours Captures Capture rate Snapper 27 380 97 891 328 0.34 General 5 440 18 861 47 0.25 Kingfish 2 042 7 716 33 0.43 Kahawai 905 2 183 19 0.87 Tarakihi 729 2 989 13 0.43 Blue cod 2 330 6 593 10 0.15 Gamefish 1 166 6 995 4 0.06 Gurnard 744 3 090 1 0.03 Rock lobster 1 026 4 492 0.00 Shellfish and kina 1 406 1 843 0.00 Hāpuku 303 1 444 0.00 Bluenose 175 1 032 0.00 All 43 646 155 130 455 0.29

This presentation is of provisional work, final results may differ.

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Largely “petrel & shearwater”

Boat ramp survey Taxon FMA 1 2 3 5 7 8 All Albatross 7 5 1 2 15 Gannet 32 32 Gull 31 1 2 1 1 6 42 Penguin 3 3 Petrel 225 4 2 231 Shag 38 2 2 3 45 Tern 19 1 20 Unidentified 65 1 1 67 All 420 8 7 3 5 12 455

This presentation is of provisional work, final results may differ.

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Largely released alive

Boat ramp survey Capture Hook Outcome Caught in net Alive 2 Hooked, externally Not removed Alive 4 Removed Alive 72 Hooked, beak/gizzard Not removed Alive 11 Removed Alive 74 Removed Dead 1 Tangled Alive 261 Dead 6 Unknown 24 All 455

This presentation is of provisional work, final results may differ.

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Data issues

Boat ramp survey

  • The form only allowed for a single incident to be recorded per

fisher, interviewers were instructed to assign other captures to other fishers in the group

  • In 46 cases, multiple captures were reported that had the

same number of captures as the number of fishers, with all the details being the same

  • Of the 7 seabirds reported as dead, 6 were repeated captures

(unkown species, tangled) in a single group

This presentation is of provisional work, final results may differ.

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Estimated seabird captures

This presentation is of provisional work, final results may differ.

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Method

Estimated seabird captures

The boat ramp survey can be used to estimate seabird captures from boat-based recreational line-fishing, by FMA and method (“Line” or “Longline”), from the product of the following terms:

  • An estimated seabird capture rate (seabirds caught per 100

hours fishing)

  • Number of hours of fishing per trip
  • Total fishing effort during 2017–18

This presentation is of provisional work, final results may differ.

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SLIDE 23

Seabird capture rate

Estimated seabird captures

  • Use a generalised linear model
  • Assume that seabird captures are proportional to length of

time fishing

  • Draw the captures from a Poisson distribution, with a rate that

varies with FMA and with method

  • The model was fitted using Bayesian methods, using BRMS,

with Normal(0, 1) priors, and 4000 samples taken from the posterior distribution of the capture rate by FMA and method capture ~ offset(log(hours)) + method + fma

This presentation is of provisional work, final results may differ.

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Seabird capture rate, model summary

Estimated seabird captures

b_fma9 b_fma8 b_fma7 b_fma5 b_fma3 b_fma2 b_methodLongline b_Intercept −3 −2 −1 1 200 400 600 800 1000 200 400 600 800 1000 200 400 600 800 1000 200 400 600 800 1000 200 400 600 800 1000 200 400 600 800 1000 200 400 600 800 1000 200 400 600 800 1000 −1.2 −1.1 −1.0 −0.9 −4 −3 −2 −1 1 −2.0 −1.5 −1.0 −0.5 0.0 −2 −1 −2 −1 1 −3 −2 −1 −1.5 −1.0 −0.5 0.0 0.5 −5 −4 −3 −2 −1

Chain

1 2 3 4

This presentation is of provisional work, final results may differ.

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Seabird capture rate

Estimated seabird captures

0.0 0.2 0.4 0.6 1 2 3 5 7 8 9

FMA Rate (captures per 100 hours) Method

Line Longline

This presentation is of provisional work, final results may differ.

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Recreating the boat ramp data

Estimated seabird captures

1 3 10 30 100 300 1000 1 3 10 30 100 300 1000

Observed seabird captures Estimated seabird captures FMA

1 2 3 5 7 8 9

Method

Line Longline

This presentation is of provisional work, final results may differ.

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Fishing hours per trip

Estimated seabird captures

From the boat ramp data, take 4000 bootstrap samples of the mean number of hours spent fishing, using each method, during each trip. The mean hours per trip were:

  • 3.79 (CV:0.008) for line fishing
  • 2.53 (CV: 0.01) for longline fishing

This presentation is of provisional work, final results may differ.

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Number of trips during 2017–18

Estimated seabird captures

Estimated trips by method and FMA were provided by NRB. Samples weer generated from log-normal distributions with the same mean and CV.

100 200 300 400 500 600 700 800 900 1 2 3 5 7 8 9

FMA Trips (x 1000) Method

Line Longline

This presentation is of provisional work, final results may differ.

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SLIDE 29

Estimated seabird captures during 2017–18

Total estimated seabird captures from small boat line and longline fishing of 12 656 (95% c.i.: 11 037 to 14 438).

2500 5000 7500 10000 12500 1 2 3 5 7 8 9

FMA Captures Method

Line Longline

This presentation is of provisional work, final results may differ.

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Spatial variation in captures

Estimated seabird captures

  • Use a CAR model, restricted to FMA1
  • Smooths the capture rate, by adjacent areas
  • Draw the captures from a Poisson distribution, with a rate that

varies with FMA and with method

  • The model was fitted using Bayesian methods, using BRMS

capture ~ offset(log(hours)) + method + car(adjacency, gr=l

This presentation is of provisional work, final results may differ.

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Seabird capture rate, model summary

Estimated seabird captures

rcar[1] sdcar car b_methodLongline b_Intercept −2 −1 1 2 200 400 600 800 1000 200 400 600 800 1000 200 400 600 800 1000 200 400 600 800 1000 200 400 600 800 1000 −2.0 −1.5 −1.0 −0.5 −3 −2 −1 1 0.00 0.25 0.50 0.75 1.00 1.0 1.5 2.0 −2 −1 1 2

Chain

1 2 3 4

This presentation is of provisional work, final results may differ.

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SLIDE 32

Seabird capture rate

Estimated seabird captures

38°S 37.5°S 37°S 36.5°S 36°S 35.5°S 35°S 34.5°S 173°E 174°E 175°E 176°E 177°E 178°E

Longitude Latitude Captures per 100 hours

Less than 0.1 0.1 to 0.2 0.2 to 0.5 0.5 to 1.0 Over 1.0

1/CV

0.5 1 2 5

This presentation is of provisional work, final results may differ.

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SLIDE 33

National Panel survey

This presentation is of provisional work, final results may differ.

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Characterisation survey

National Panel survey

  • There were 1847 responses to the NPS characterisation

survey

  • 1203 fishers answered the question relating to seabirds

(“During the last fishing year have seabirds disrupted your fishing activity?”)

  • 295 (24.5%) of fishers answered “yes”

This presentation is of provisional work, final results may differ.

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SLIDE 35

Nature of the interaction

National Panel survey

Of 404 responses to this question (people could answer multiple times):

  • 33 selected “By becoming entangled in your lines”
  • 55 selected “By taking a baited hook and needing to be

unhooked”

This presentation is of provisional work, final results may differ.

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Data issues

National Panel survey

  • Data provided by MPI were not linked to the fishers’ responses

through the year

  • Low participation in the characterisation survey
  • A single question was asked about fishing throughout the

year, which would make analysis difficult

  • Questions were across multiple incidents

This presentation is of provisional work, final results may differ.

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Discussion

This presentation is of provisional work, final results may differ.

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Distribution of recreational fishing

Discussion

  • To analyse impact using a risk framework requires a

distribution of recreational fishing

  • This is only available from the aerial survey, and was last

updated from 2011–12 data

  • Not available for general recreational fishing, and not routinely

produced as an output of the recreational surveys

  • Recommend that maps of annual hours of recreational

fishing, by method, are generated

This presentation is of provisional work, final results may differ.

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Consistent reporting

Discussion

  • Require reporting of captures that are linked to effort (to

allow reporting of rates)

  • Recommend reporting of individual captures, and from

individual fishing trips

  • Collect the same information from all surveys, and via ad hoc

reporting, such as when people ring the DOC hotline

This presentation is of provisional work, final results may differ.

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SLIDE 40

Improving reporting

Discussion

  • Best information is from the boat ramp survey (because of

the scale), but this is limited to boat fishing

  • The NPS diary survey allows, in principle, for reporting to be
  • btained from representative fishing methods
  • Extend to include all protected species
  • Self-reporting methods (such as a fishing diary app) could

extend the reach

  • Roving surveys may be needed to reach, for example, kontiki

fishers on beaches were shark captures have been known to

  • ccur

This presentation is of provisional work, final results may differ.

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Self reporting

Discussion

  • The NPS indicates that reporting from around 1000 fishers

resulted in around 100 seabird captures reported annually

  • Any self-reporting should aim for at least that scale to be

useful

  • Challenges include representivity (methods such as set net

and kontiki fishing may have different demographics from rod and line fishing)

  • Data are more valuable if fishing effort is recorded, even if

there are no captures

This presentation is of provisional work, final results may differ.

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Self reporting

Discussion

  • Any self-reporting will require fishers to be motivated
  • In addition, self-reporting could be used for reporting

captures, even if the effort is not reported

  • For species like Hector’s dolphin, people are likely to be

worried about the implications of reporting a captures

This presentation is of provisional work, final results may differ.

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Recommendations of Hartill and Thompson (2006)

Discussion

  • Focus on developing standards and an interface for collecting

self-reporting data

  • The same interface could support data from fishing

competitions, ramp surveys, club records, fishing diaries, government applications

  • Consider data governance and ownership issues from the

start, with a focus on open data

This presentation is of provisional work, final results may differ.

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Summary

Discussion

  • Around 10 000 seabird captures or interactions annually in

FMA1, with uncertain mortality

  • Spatial risk assessment will require distributions of

recreational fishing effort

  • No quantified data sources are available for any protected

species, other than seabirds

  • Improvements to data collection will be needed to

understand the extent and impact of these captures

This presentation is of provisional work, final results may differ.