DFO HERRING SCIENCE AND MANAGEMENT Presented for: Prey Availability - - PowerPoint PPT Presentation

DFO HERRING SCIENCE AND MANAGEMENT

Jaclyn Cleary & Victoria Postlethwaite

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Presented for: Prey Availability TWG, May 8, 2019

Annual data and stock assessment programs are conducted coast- wide 5 major and 2 minor stock assessment areas

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Southern BC Herring stocks

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Recent 10 years, the main migratory stock spawns primarily in Areas 14 & 17N; little to no spawning below Dodd Narrows Past 15 years, low spawning levels in Esperanza/ Nuchatlaht; Hesquiat/Ahousat; Barkley Sound

Spring spawning (inshore) Summer feeding (offshore)

SOG

• General migratory pattern is for age

2+ herring to move out of SOG post spawning (April/May) and move into the west coast feeding areas

• Juvenile herring are thought to

remain within the Strait of Georgia until at age 2 WCVI herring share feeding grounds with SOG stock (May – Oct)

Herring Migratory Patterns

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Herring Science Key Programs

• Annual data collections
• Spawn survey, Biological samples, Catch data
• Annual stock assessment (Fall)
• Stock trends, herring spawn distribution
• Current stock status, 1-year projections
• Herring MSE
• Objectives and management procedures

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Herring Stock Assessment: goal of stock assessment is to describe past and current status of a fish stock, make predictions about the future in order to make recommendations for sustainable harvest levels ‘model’ Number of fish; current biomass

minus Deaths (mortality and catch) plus New arrivals

Forecast for next spring D A T A

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Implement decision rules

Is area

• pen/closed?

What is TAC?

Strait of Georgia herring: stock trends and reference points

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LRP (0.3B0) + 90% CI Long- term average biomass

Spawning biomass + 90% confidence interval

2010 2017

Recent spawn concentrating in 14 & 17N relative to historical periods. *Change in survey methods makes it hard to differentiate changes attributable to changes in survey methods, and those which are biological*

1971-1980* 2001-2010

SOG Spawn Distribution Over Time

WCVI herring: stock trends and reference points

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LRP (0.3B0) + 90% CI

Spawning biomass + 90% confidence interval

1950 ‘60 ‘70 ’80 ‘90 2000 ’10

2018

WCVI Spawn Distribution

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1950s 2010s

Annual assessment advice includes:

• Science advice on:
• Biomass trends and herring distribution
• Biology (size and age structure)
• 1-year biomass forecasts and recommendations

for sustainable harvest levels

• Communication of uncertainty and risk, e.g.:
• Biomass + confidence intervals
• Probability of avoiding conservation limits

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Incorporation of Science Advice

• Fisheries management receives annual science

advice on 5 major herring stock assessment areas

• Stock biomass and forecast
• Stock levels compared to biological reference

points (LRP)

• Catch calculation from application of

management procedures (previously decision tables)

• Aims to ensure that advice and subsequent

management decisions are robust to uncertainty

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Incorporation of Science Advice

• Management approach incorporated into IFMP
• Consultation on harvest levels, commercial

allocations, management measures

• Through advisory board processes and draft IFMP

(mainly in September-December)

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Herring Advisory Process

• Integrated Herring Harvest Planning Committee (IHHPC)
• First Nations
• Spawn on kelp fishery
• Herring Industry Advisory Board
• Special use fishery
• Marine Conservation Caucus (MCC)
• Sport Fishing Advisory Board (SFAB)
• Province of BC
• Herring Industry Advisory Board (HIAB)
• Seine and gillnet representatives
• Processors
• First Nations – Bilateral meetings
• Other groups as needed (e.g. Conservancy Hornby

Island)

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Management Measures

• Harvest levels
• MSE results to date support continued

application of the 20% harvest rate for the current biomass level in the Strait of Georgia

• West Coast of Vancouver Island remained

closed to support stock rebuilding

• Open areas
• Closure of areas where there is an absence of

spawning herring

• Closure of First Nations FSC harvest areas

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Research

• Interplay of food supply and predation impact
• n herring survival and production is complex

and not readily predictable (Schweigert et al. 2010)

• Biological reference points (limit reference

point, upper stock reference point) have been developed

• Application of the LRP has been completed
• Renewal of the management system is
• ngoing, including a Management Strategy

Evaluation process (first cycle complete for SOG and WCVI)

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