Modelling of impacts of fishing-related mortality on New Zealand seabird populations

Project: Modelling of impacts of fishing-related mortality on New Zealand seabird populations.
Project Code: ENV2004/05
Start Date: 1 October 2004
Completion Date: 30 September 2006
Vessel Use: Nil

Overall Objective:

1. To provide assessments of the ability of selected seabird populations to sustain fisheries removals within the New Zealand EEZ.

Specific Objectives:

1. To examine and identify modelling approaches to analyse seabird demographic impacts that may be occurring as a result of fisheries mortality.
2. To compile databases of available demographic and distributional data on selected seabirds affected by fisheries mortality and New Zealand fisheries and estimate key population parameters and seasonal distribution for each species.
3. To estimate rates of removals related to fishing activities in New Zealand for selected seabird species, where possible by age class and sex.
4. To describe the spatial overlap of seabird distributions at sea, with fisheries where the risk of incidental mortality has been demonstrated to be moderate to high.
5. To examine the potential for factors other than fisheries removals within the New Zealand zone to influence the population dynamics of the selected study species.
6. To characterise selected seabird populations’ abilities to sustain removals related to fishing operations within the New Zealand EEZ, and to recommend, where possible environmental standards for assessing the sustainability of selected fishing operations in relation to impacts on seabird populations.
7. To advise on data collection for selected species, to enhance management of fisheries threats to population viability.

Rationale:

General

Under the sustainability measures set out in the Fisheries Act (1996, s 15), the fishing-related mortality of marine mammals or other wildlife may be managed to avoid, remedy or mitigate any adverse effects of fishing on the related protected species.

Further, the National Plan of Action: Seabirds (Department of Conservation and Ministry of Fisheries 2003), currently under consultation, calls for the development of research that enables a species by species approach to managing the effects of fishing on seabird populations. Information to underpin a management framework, that recognises the responsibility of individual fisheries or fishers, in contributing to changes in population status for protected seabird species populations, is lacking.

Due to a lack of integrated analyses of seabird incidental catch and demographic data, it is unclear currently, where the greatest efforts need to be applied to alleviate pressure on populations impacted by moderate to high levels of mortality, relative to their population size. This research is intended to examine the feasibility of a species approach to management of seabird population impacts of New Zealand fisheries, using existing demographic and observer data. The research is intended to inform a range of management options, including the development of codes of practice.

While several long-term data sets which would allow estimation of key population parameters for several seabirds species which suffer mortality in fishing operations have been identified (MacKenzie et al. unpublished report), most data have largely been collected in an ad hoc manner, potentially limiting the power of the proposed analyses to determine the fine scale influence of fisheries on species populations. However, the development of modelling methodologies, which can be applied with patchy data, will enable best use of existing data to manage seabird-fishery interactions.

The approach adopted in the Ministry of Fisheries draft Strategy for Managing the Environmental Effects of Fishing, to utilise standards, for assessing the sustainability of fishing, requires more detailed information at a species level for seabirds affected by fisheries mortality, to define appropriate standards. This research will examine the feasibility of using a species based approach to setting environmental standards to manage seabird-fishery interactions.

Should a fully age-structured stochastic modelling approach be adopted for this research, the work will focus on up to three species of seabird in the first year, with delivery of results on objectives 2-6 during this period. Contingent on the results of these investigations, agestructured models of up to 5 other seabird species will be compiled during the second years of the programme.

Objective 1

There is likely to be considerable variability in the coverage and quality of data available for research into the population effects of fisheries mortality on seabirds in New Zealand. Consequently modelling these data is unlikely to be straightforward. The research provider will be expected to examine the available data to identify the most appropriate modelling approaches.

Objective 2

The Ministry of Fisheries has been working with data-holders from a range of agencies to secure agreements for access to published and unpublished data to assist this research.

The aim of this objective is to create a database comprising demographic and distributional data on selected seabirds affected by fisheries mortality and New Zealand fisheries and estimate key population parameters and seasonal distribution for each species. Ministry of Fisheries data management requirements will need to be met.

Objective 3

This objective links directly to outputs from previous programmes undertaken by the Ministry of Fisheries, (e.g.ENV2001/01 Estimation of seabird captures in New Zealand fisheries). Some reanalysis of the data may be needed to integrate the results with population modelling.

Objective 4

While mortality for some species of seabird is observed directly through Ministry of Fisheries Observer programmes, the level of mortality is likely to be underestimated for some species, due to incomplete knowledge about the range of habitats they occupy and changes in seabird range through the year. Using data from objective 2 on seabird distribution for selected species involved in the modelling work, an analysis will be undertaken to assess which fisheries have potential to impact on seabird populations, through incidental mortality.

Objective 5

Factors other than fisheries mortality in the New Zealand zone have potential to impact on populations of seabirds nesting within the EEZ. By a literature search and examination of unpublished information, pertaining to selected seabird species involved in the modelling, potential for these factors to play a role in influencing population viability will be examined.

Objective 6

The Ministry of Fisheries’ Draft Strategy for Managing the Environmental Effects of Fishing calls for environmental standards to be set, to manage such effects as population impacts of fishing on seabird populations. The outcome of the modelling work, will be informed levels of mortality than can be sustained for selected New Zealand seabirds species. These will inform, directly, management procedures such as codes of practice or mandatory catch limits, in cases where there is a high-risk of deleterious population effects occurring to particular seabird species.

Objective 7

The research will inform the directed gathering of new information on seabird populations, their distributions at sea, or the placement of observer cover. A prescriptive analysis of data collection methods necessary for further work in this area will be compiled.

References:

Ministry of Fisheries and Department of Conservation. 2003. National Plan of Action to reduce the incidental catch of seabirds in New Zealand fisheries. Draft for consultation.

Mackenzie, D. Fletcher, D. and Scofield, P. unpublished. Inventory of seabird data resources. Draft Final Report for the Ministry of Fisheries.

Strategic Relevance

This research addresses the environmental principle of the 19965 Act that “…associated or dependent species should be maintained above a level that ensures their long-term viability…” and the strategy for marine environment research “…to develop and apply methods to ensure the use of fisheries resources is compatible with the requirements to avoid, remedy or mitigate any adverse effects of fishing on the marine environment, to maintain biological diversity and to protect habitat of particular significance for fisheries management”. This project forms a part of the Aquatic Environment research theme ‘…to determine the direct effects of fishing on associated or dependent species…’. This project is therefore consistent with the Aquatic Environment Research section of the Ministry of Fisheries Strategic Research Directions document.

Cost Recovery Information:

The percentage allocation for this project will be attributed to the following Fishstocks according to rule 7 schedule 3 of the Fisheries (Cost Recovery) Rules 2001:

• All ALB, BAR, BIG, BNS, HAK, HOK, JMA, LIN, ORH, RCO, SBW, SCI, SQU, SSO, STN, SWA, SWO, YFN Fishstocks

The project is estimated to cost between $400,000 — $500,000.