agriculture.vic.gov.auagriculture.vic.gov.au/__data/assets/word_doc/0010/... · Web viewRock Lobster Fishery Harvest Strategy Information Paper ii Rock Lobster Fishery Harvest Strategy

Draft Rock Lobster Fishery Harvest Strategy

An Information Paper

December 2015

Contents

Introduction____________________________________________________________________________1

What is a harvest strategy?_______________________________________________________________22009 Rock Lobster Harvest Strategy 2Why has the harvest strategy been changed? 2

Proposed Rock Lobster Fishery harvest strategy_____________________________________________3What is the aim of the new harvest strategy? 3What are the main components of the harvest strategy? 3What is standardised CPUE and why is it being used? 3Getting the harvest rate right 3Rationale for choosing these harvest rates 4Other harvest rate options considered 5

How does the strategy work?_____________________________________________________________5Harvest rate and limit reference points 5Pre-recruit index 6Egg production 6TACC Caps 6One-jump rule 6TACC Tables 7

How will TACCs be set?__________________________________________________________________8Decision Rules 8

Conclusion_____________________________________________________________________________9

References_____________________________________________________________________________9

Appendix 1____________________________________________________________________________10What are the components of a harvest strategy? 10

Appendix 2____________________________________________________________________________11Key Fishery Statistics – Western Zone 11Key Fishery Statistics – Eastern Zone 12

Rock Lobster Fishery Harvest Strategy Information Paperii

Introduction

This paper provides an overview of the proposed harvest strategy for the Victorian Rock Lobster Fishery. It also explains how the harvest strategy was developed and why certain parameters were chosen.

The proposed strategy is based on commercial catch rate and has been designed to be more transparent and less reliant on model outputs. The previous management plan, put in place in 2009, used a harvest strategy with an explicit rebuilding target and timeline. Rebuilding the stock required substantial reductions in total allowable commercial catches but resulted in improvements in catch rate and stock levels.

Despite these improvements, the catch rates in Victoria remain the lowest of the rock lobster fisheries in Australia and New Zealand. A common goal for the Government and Industry is to ensure that the fishery has the capacity to continue rebuilding and to future-proof itself should any unfavourable conditions (e.g. environmental changes, low recruitment, falling egg production) arise in the future.

The proposed harvest strategy takes a precautionary approach and uses egg production, standardised catch rate and numbers of juvenile lobsters in the population as determinants for setting the annual total allowable commercial catches.

The strategy aims to be precautionary enough to ensure that the conditions for export approval required by the Environment Protection and Biodiversity Conservation Act 199 and that the sustainability requirements of the Status of Key Australian Fish Stocks are met.

The proposed harvest strategy is part of the new draft Rock Lobster Fishery Management Plan and was developed by Fisheries Victoria with the assistance of an independently chaired Steering Committee. The Steering Committee was comprised of representatives from the commercial and recreational fishing, conservation, and government sectors and included an independent scientific advisor.

The Management Plan and harvest strategy have been released for public consultation as per the requirements in the Fisheries Act 1995.

The Management Plan and the harvest strategy will be used to set the TACCs in the Rock Lobster Fishery for the season commencing 1 July 2016 and will be in effect for a minimum of five years.

Rock Lobster Fishery Harvest Strategy Information Paper1

What is a harvest strategy?

Put simply, harvest strategies set catch limits for commercial fisheries and provide a clear framework for how those catch limits will be set. Harvest strategies use a systematic approach to assess the status of a fishery and a include set of rules that are used to determine what the catch limits will be. Because these rules are set out in advance, fishers and fishery managers know what actions will be taken in response to the conditions in the fishery.

2009 Rock Lobster Harvest StrategyThe previous harvest strategy was designed at a time when the fishery was experiencing some of the lowest catch rates in its history and below average recruitment levels. The aim of the harvest strategy was therefore to rebuild the rock lobsters stocks in both commercial zones of the fishery.

To ensure that rebuilding took place and was kept on track, a target of 40% of the stock level in 1951 by the year 2020 was used.

Since the introduction of that harvest strategy in 2009, the declining trend in catch rate in both zones has been reversed. Catch rates in the Western Zone increased from 0.37kg/pot lift to 0.56kg/pot lift in 2013/14 and from 0.38kg.pot lift to 0.52kg/pot lift in the Eastern Zone. This improvement in catch rate reflects the improvement in the stock in the fishery (the available biomass) (Figure 1).

To achieve these increases in catch rate and stock, it has been necessary to reduce annual total allowable commercial catches.

Figure 1: Abundance of legally-sized rock lobsters in each zone. Improvements are evident from 2009 onwards.

Why has the harvest strategy been changed? While the 2009 harvest strategy was successful in rebuilding the rock lobster stock, it was heavily reliant on a stock assessment model to estimate future conditions in the fishery and to set the TACC each year. Because of this reliance, it was difficult for fishers and fishery managers to predict and plan for future TACCs until the modelling had been completed.

There was therefore a need for a harvest strategy that was simple, straightforward and which allowed fishers to be able to better predict upcoming TACCs using fishery data available throughout the season.

For that reason, the new harvest strategy uses catch rate as a basis to determine the TACC.


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2009 Harvest Strategy

Proposed Rock Lobster Fishery harvest strategy

What is the aim of the new harvest strategy?The harvest strategy aims to achieve two main operational objectives, both of which link to the overarching objectives in the Management Plan. These are:

1. Continue to rebuild the rock lobster population by setting appropriately conservative TACCs on an annual basis.

2. Maintain standardised catch rates above 0.40 kg/pot lift.

What are the main components of the harvest strategy?1. The harvest strategy is a catch rate-based strategy that uses standardised catch per unit effort

(CPUE).

2. TACCs are predetermined for a particular catch rate and are based on harvesting a set proportion of the stock (the harvest rate).

3. The harvest rate is constant unless the catch rate falls below 0.4kg/pot lift (the upper limit reference point, refer to Appendix 1), when it is incrementally reduced. The fishery will be closed if the catch rate falls to 0.25kg/pot lift (the lower limit reference point) or less.

4. TACCs are set using the standardised CPUE in that year’s stock assessment and a pre-recruit index in combination with a set of decision rules that determine whether the annual TACC is increased or decreased in the following season.

What is standardised CPUE and why is it being used?Catch rate, or CPUE, is representative of rock lobster abundance.

Catch rates are, however, influenced by factors that are not related to abundance including changes in fishing areas locations, fishing experience and changes in fishing gear that make fishers more efficient.

To get the most accurate estimate of the abundance in a zone, data from the catch and effort logbooks is, therefore, standardised for differences among regions, depth ranges, fishing seasons, months, fishers and vessels.

Standardising catch rates allows fishery managers to accurately compare catch rates between years and to see changes in abundance.

It is acknowledged that there continues to be concern from Industry regarding the factors being standardised and the method of standardisation. These will be evaluated in 2016.

Getting the harvest rate rightThe foundation of this harvest strategy is the harvest rate (also referred to as exploitation rate), which is the proportion of the available stock that can be caught.

Setting the right harvest rate is a balance between sustainability of the resource and maximising the economic value of the industry.


Setting the harvest rate too low may rebuild the stock faster but it could result in lower TACCs in the short-term and a challenging economic situation for fishers. A harvest rate that is too high can result in minimal to no increase in biomass over time and therefore no improvement to the stock status, catch rates, economic efficiency or profitability of the industry.

The proposed harvest strategy does not include a rebuilding target so it is important that the harvest rate is conservative enough to ensure that the stock rebuilds, that catch rates improve, that profits are maximised and that the objectives of the harvest strategy and management plan can be met.

The harvest rates in the proposed harvest strategy are 30% for the Western Zone and 15% for the Eastern Zone. These values mean that, in the case of the Western Zone for example, 30% of the total stock above legal size can be caught and 15% in the Eastern Zone.

Rationale for choosing these harvest ratesBetween 2011/12 and 2013/14, the harvest rates in the Western Zone have been between 38% and 39% of the available stock biomass. Over the same timeframe, harvest rates in the Eastern Zone have been 21%, 16% and 18% per season (refer to Figures 5 and 8 in Appendix 2).

The harvest rates used for this harvest strategy are therefore a slight reduction on the recent averages in each zone.

While there have been improvements in stock levels, there are concerns about the capacity of the fishery to continue rebuilding and to future-proof itself should any unfavourable conditions (such as environmental changes) arise in the future:

Levels of egg production are low across the whole of south-eastern Australia. The numbers of pre-recruits and undersize lobsters continue to be below average in Victoria. Biomass levels in the fishery are about 50% of 1978 levels (1978 = catch and effort logbooks

introduced). Levels of CPUE are still reasonably low at around 0.55kg/pot lift (unstandardised) in each zone

and have not improved for the last three years. The CPUEs in Victoria continue to be some of the lowest values in rock lobster fisheries in the

country and overseas. Although stock has been rebuilding, the numbers of lobsters that have been growing through

the fishery have come from higher levels of recruitment and the indications are that these trends will not continue.

High beach prices have kept the fishery profitable but profitability should come from increased catch rates and a decreased effort to catch the quota.

A summary of a number of important fishery trends can be found in Appendix 2.

These trends emphasise that a precautionary approach is necessary and that the lower harvest rates are the only way to ensure stocks will continue rebuild and that catch rates and industry profitability improves.


Other harvest rate options consideredA range of harvest rates were considered to make sure the most appropriate was chosen for each zone. An examination of the likely future effects of the different options was also undertaken by modelling the outputs going forward 15 years. For the Western Zone, harvest rates of 25%, 30%, 32.5% and 35% were considered and for the Eastern Zone, 15%, 17.5% and 20%.

Noting that modelling future outcomes is not exact, in both zones, the most conservative harvest rates gave the most immediate stock rebuilds, considerably higher levels of CPUE and much lower levels of effort (number of pot lifts) to catch the TACCs. The levels of stock growth were also considerably higher under these scenarios. Consideration was therefore given to the potential economic impact on industry profitability through a potential reduction in TACC.

Conversely, under the 35% and 20% harvest rate scenarios for the Western and Eastern Zones, respectively, the improvements to the biomass and the CPUE over the 15-year time frame were almost negligible. Consideration was therefore needed regarding whether these scenarios supported the objectives of the Fisheries Act and the Management Plan to rebuild the stock and make the industry more profitable.

The most viable options that supported a strong rebuild in the stock as well as a reduction in effort without creating a significant burden on industry were the harvest rates of 30% and 15% for the Western and Eastern Zones, respectively.

How does the strategy work?

Harvest rate and limit reference pointsUnder this harvest strategy, harvest rates remain constant as long as the standardised CPUE remains above the upper limit reference point (Figure 2). This means that as the stock biomass grows, the TACC will also increase (i.e. 30% of a 500 tonne stock biomass is 150 tonne and 30% of a 1000 tonne stock is 300 tonnes).

When the standardised CPUE is above the limit reference point and improving, the TACCs can be increased as long as certain conditions are met. These conditions are explained in the following section.

The limit reference point acts like a safety measure. In the case of this harvest strategy, an upper and a lower limit reference point have been established; both are CPUE-based. If the annual standardised CPUE falls below the upper limit reference point, the harvest rate is decreased each year until the CPUE is again above the upper limit.

If the standardised CPUE falls below lower limit reference point, the fishery will be closed to all fishing.

The upper limit reference point was determined based on the objective in the harvest strategy to stay above a standardised CPUE of 0.40kg/pot lift.

The lower limit reference point, a standardised CPUE of 0.25kg/pot lift, was chosen based on the lowest values experienced in the fishery.


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Figure 2. Theoretical construction of the proposed harvest strategy framework.

Pre-recruit indexThe pre-recruit index (PRI) is an indicator of the likely future stock levels in the fishery and is used as a threshold value in this harvest strategy. A threshold value sets a baseline with which to make comparisons, i.e. whether the PRI is above or below the threshold value. The threshold values for the PRI will be determined using the average number of undersize lobsters per pot lift from the fixed site surveys over a particular length of time.

The threshold PRIs for each zone will be established during the first year of the harvest strategy. The PRI for that year must be above the threshold level for a TACC increase in the zone to be considered.

Egg productionEgg production is an estimate of the spawning capacity of the stock. It is a crucial determinant of the health of the stock and is used in this strategy as a primary indicator in the decision rules. A measure of egg production has been set that is equivalent to 20% of the estimated egg production in 1951 (the beginning of commercial fishing records). To be able to consider an increase in TACC, the egg production must be above this threshold.

TACC CapsAn upper limit, or cap, on possible TACC levels has been included in this harvest strategy. The cap for the Western Zone is 300 tonne and is 70 tonne for the Eastern Zone. This means that, over the life of the harvest strategy, the TACCs cannot go above a certain level even if the standardised CPUE values are continually increasing.

One-jump ruleTo maintain the focus on rebuilding the rock lobster stocks, the TACCs can only be increased by one level at any one time.


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30%Constant harvest rate

Upper limit reference pointHarvest rate decreases

Lower limit reference pointFishery closed

Standardised CPUE (kg/pot lift)

Harvest rate

TACC TablesThe levels of TACC are pre-set and based on the chosen harvest rate. The values of the TACCs and the corresponding CPUE are in Tables 2 and 3.

These tables, in association with the decision rules (see next section) will be used to set the TACCs for the fishery over the life of the Management Plan.

Table 2: CPUE bands and corresponding TACC levels for the Western Zone

WESTERN ZONE TACC LEVELS

CPUE band TACC Levels - with 300t cap

<0.25 00.25 - <0.275 180.275 - <0.3 390.3 - <0.325 64

0.325 - <0.35 920.35 - <0.375 1230.375 - <0.4 1580.4 - <0.45 2020.45 - <0.5 2260.5 - <0.55 2500.55 - <0.6 2740.6 - <0.65 2980.65 - <0.7 3000.7 - <0.75 3000.75 - <0.8 300

Table 3: CPUE bands and corresponding TACC levels for the Eastern Zone

EASTERN ZONE TACC LEVELS

CPUE band TACC Levels - with 70t cap

<0.25 00.25 - <0.275 40.275 - <0.3 80.3 - <0.325 14

0.325 - <0.35 200.35 - <0.375 260.375 - <0.4 330.4 - <0.45 420.45 - <0.5 470.5 - <0.55 510.55 - <0.6 560.6 - <0.65 600.65 - <0.7 650.7 - <0.75 690.75 - <0.8 70


How will TACCs be set?

The annual TACC is determined using a combination of the TACC tables (see previous section) and the PRI and is set using decision rules. The decision rules used in the harvest strategy provide clear guidance on the TACC-setting process by defining how estimates of standardised CPUE and PRI should be interpreted and linking them to a set of rules for adjusting the TACC.

Decision Rules

1. Egg production. Modelled estimated egg production must be above the limit reference point of 20% of the egg production in 1951 (E1951)with a 90% probability. If this decision rule is not met, the TACC will be determined using the rock lobster fishery projection model to ensure that the TACC returns the egg production to above the limit reference point within two years with a 90% probability.

This decision rule must be satisfied before the CPUE-based harvest strategy can be used to set the TACC.

2. TACC Determination. When Decision Rule #1 has been met, the TACC is set using the standardised CPUE tables.

Using the standardised CPUE of the preceding season, the appropriate CPUE band is identified and the corresponding TACC level is set according to the following conditions:

a. The TACC can be increased to the next level when:

the standardised CPUE is in a band higher than in the previous season; and the PRI is at or above the trigger point of xx undersize per pot lift for the

Western Zone or xx undersize per pot lift for the Eastern Zone (Note: these values will be determined over 2016/17 by the Rock Lobster Resource Assessment Group).

The TACC can only be increased one level per year.

b. The TACC will remain at the same level when:

i. the standardised CPUE remains in the current band;OR

ii. the standardised CPUE has increased to a higher band but the PRI is below the trigger point.

c. The TACC will be decreased when:

the standardised CPUE has decreased into any lower band.

The TACC will be set at the level that corresponds to the standardised CPUE.

3. TACC Cap. A TACC cap of 300 tonnes in the Western Zone and 70 tonnes in the Eastern Zone will be used over the life of the harvest strategy.


Conclusion

The draft Rock Lobster Fishery Management Plan and harvest strategy have been released for public comment.

Written submissions can be made by Friday, 4 March 2016 to:

The Rock Lobster Fishery Manager2A Bellarine HighwayQueenscliff VIC 3226

or [email protected].

At the conclusion of the public consultation, comments received will be reviewed and any necessary changes or amendments will be made. The Management Plan will then be published and the harvest strategy used to set the TACCs in the Rock Lobster Fishery for the season commencing 1 July 2016.

Any written submissions received in relation to the consultation being conducted by Fisheries Victoria will be published on the Department's website. In making a submission, unless the person making the submission indicates to the contrary, they will be consenting to their submission, including their name only, being published on the Department's website for 90 days from the conclusion of the consultative process.

References

Sloane, S. R., Smith, A. D. M., Gardner, C., Crosthwaite, K., Triantafillos, L., Jefferies, B. and Kimber, N. (2014). National Guidelines to Develop Fishery Harvest Strategies. FRDC Report – Project 2010/061. Primary Industries and Regions, South Australia, Adelaide, March

Fletcher, W. J., Chesson, J., Fisher, M., Sainsbury, K., Hundloe, T.M.F., Smith, A.D.M., and Whitworth, B. (2002). National ESD Reporting Framework for Australian Fisheries: The ‘How To’ Guide for Wild Capture Fisheries. FRDC Project 2000/145, Canberra, Australia, 120p.


mailto:[email protected]

Appendix 1

What are the components of a harvest strategy?In practice, there are a number of components that make up a harvest strategy. Most commonly, harvest strategies are written in combination with a fishery management plan. The fishery management plan sets out high level strategic management objectives to guide the direction of the fishery and these are translated into operational objectives in the harvest strategy. Operational objectives need to be easily measured and linked to performance indicators, reference points and decision rules. The operational objective, performance indicator and reference point form a package and are the system used to measure the performance of the fishery (Sloan et al 2014, Fletcher et al 2002)

Operational objectives are practical and measureable, and explicitly state what is intended by the harvest strategy.

Performance indicators are quantities that can be measured and are used to track the fishery’s performance against achieving an operational objective (Fletcher et al 2002).

Reference points are the ‘benchmarks’ for the performance indicators and are linked to setting acceptable levels of biological impact on the fishery. There are three types of reference points: target, limit and trigger. If, during the assessment of the fishery, a reference point is breached, the pre-determined management action will result, consistent with established decision rules (Sloan et al 2014).

o A target reference point represents a fishery indicator that is ideal or at which management should aim. Often, target reference points are based on economic or social outcomes (e.g. high catch rates, achieving maximum economic yield).

o A limit reference point sets the level at which that indicator for the fishery should not go below. These reference points and associated indicators are usually connected to biological sustainability of the fishery.

o A trigger reference point represents the point when a substantial change occurs. They are often set at levels which, if reached, provide an alert that stock trends in the fishery have deteriorated.

Decision rules are predetermined management responses that relate to the status of the fishery as determined through the fishery assessments.


Decision RulesReference Points

Performance Indicators

Harvest Strategy

Management Plan High level strategic objectives

Operational objectives

Appendix 2

Key Fishery Statistics – Western Zone

Key Fishery Statistics – Eastern Zone

Figure 3. Model estimated level of egg production through time in the WZ with a probability of 75%.

Figure 4. Nominal and standardised catch rates (kg/pot lift) in the WZ.

Figure 5. Relationship between abundance of legally-sized lobsters (available biomass) and exploitation rate (catch/available biomass) in the WZ.


Figure 6. Model estimated level of egg production through time in the EZ with a probability of 75%.

Figure 7. Nominal and standardised catch rates (kg/pot lift) in the EZ.

Figure 8. Relationship between abundance of legally-sized lobsters (available biomass) and exploitation rate (catch/available biomass) in the EZ.

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agriculture.vic.gov.auagriculture.vic.gov.au/__data/assets/word_doc/0010/... · Web viewRock Lobster Fishery Harvest Strategy Information Paper ii Rock Lobster Fishery Harvest Strategy