SUCCESSFUL FISH STOCK ASSESSMENT PROJECTS
Fish Stock Assessment for South African Pelagic Fishing Industry Association
OLSPS Marine conducted two studies relating to the two-stock hypothesis of the South African sardine fishery, resulting in the following documents being published:
1. A conceptual analysis and review of the development of a two-stock hypothesis for sardine, its current status, outputs and estimates required from the scientific process, and an outline of alternative hypotheses and/or hypotheses that still need to be scientifically evaluated
2. Equilibrium harvesting consequences in a deterministic two-component sardine model with one-way migration Fish Stock Assessment for South African Pelagic Fishing Industry Association
Fish Stock Assessment for The South African Deep-Sea Trawling Industry Association
OLSPS Marine has been conducting studies for the South African Hake Fishery since 1991. A sample of such studies include:
- Conducting a quantitative evaluation of the relative biological merits of trawling and long-lining;
- Reviewing a new interpretation of the commercial catch rate database using the General Linear Modelling (GLM) method and finding that an increase in the minimum legal codend mesh size in 1976 reduced catch rates below economic breakeven thresholds.
- Submitting numerous innovations to stock assessment models and developing a version thereof which incorporates cannibalism;
- The development of input controls for the fishery
- Ongoing consultation with the association
Fish Stock Assessment for Fishwell Consulting, Australia and the Australian Fisheries Management Authority (AFMA)
OLSPS Marine used a modelling framework to simulate the biological and economic risk of the draft harvesting strategy for small pelagics produced by AFMA. This modelling framework assumes that any species and area combination can be modelled using a standard single species population approach. Results were presented in either deterministic or stochastic format, for four species, namely Redbait, Jack mackerel and Blue mackerel.
Fish Stock Assessment for South African Squid Management Industry Association
Since 2006, OLSPS Marine has been involved in the management of the Loligo vulgaris reynaudii (chokka squid) resource off the South African coast through, inter-alia, attendance at Scientific Working Group deliberations, an extensive review of scientific data available for the resource in 2006, a development of the Bayesian stock assessment model for the resource and facilitation of a workshop between government and industry in 2009. At present OLSPS Marine attends scientific working group meetings as a consultant to SASMIA (the South African Squid Management Industry Association).
Stock Assessment for the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR)
OLSPS Marine was involved in the initial stock assessment of the Antarctic and Patagonian Toothfish for use in total allowable catch estimates.
FISHERIES MANAGEMENT INTERACTIVE TOOLS CREATED BY OLSPS MARINE
Fish Stock Assessment Interactive Tools for West Coast Rock Lobster Association and Hake Fishery of South Africa
On behalf of the West Coast Rock Lobster Association of South Africa, OLSPS Marine has developed an algorithm to estimate trends in somatic growth rates for West Coast rock lobster Jasus lalandii. This is ongoing work which is carried out each year prior to management deliberations for the resource involving government and industry stakeholders.
An Interactive tool was created by OLSPS Marine which integrates the use of Microsoft Excel and Microsoft Access to filter and spatially display the distribution of catch-effort and sampled data for the South Cost Rock Lobster Fishery and the South African Hake Fishery in South Africa.
OLSPS Marine has also developed and maintained a species splitting algorithms for South African hake. Hake in South Africa consists of the two species Merluccius paradoxus and Merluccius capensis. Distinction between species is not readily achievable by fishing crews since the differences between the species are subtle and require a scientifically trained observer.
Retrospective identification of species is therefore carried out making use of a mathematical model that relates the proportion of each species to the depth, year, size and longitude and latitude of fishing. In this project OLSPS Marine was engaged to update the species splitting algorithm based on fresh observer data since 2010.
Excel spreadsheets was developed by OLSPS Marine which contained embedded Visual Basic procedures, designed to facilitate the planning of fishing permit requests in accordance with the effort controls applied in the offshore hake trawl fishery.
OLSPS Marine has submitted numerous innovations to stock assessment models for the South African hake trawl fishery and developing a version thereof which incorporates cannibalism.
Fish Stock Assessment Interactive Tools for Agriculture Organisation of the United Nations
OLSPS Marine developed a model for the Food and Agriculture Organisation of the United Nations (FAO) in which the number of seagoing lives at risk is related to the fishing effort in the fishery.