Aquat. Living Resour.
Volume 35, 2022
|Number of page(s)||17|
|Published online||07 October 2022|
Analyses of the composite yield per recruit model CYPR14 for inferring plausible fishing mortality targets of fish in the tropics
Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, 100 8th Avenue, SE, St. Petersburg, FL 33701–5095, USA
* Corresponding author: Joseph.Munyandorero@MyFWC.com
Handling Editor: David Kaplan
Accepted: 13 August 2022
Stocks' yield and size per recruit are widely used to provide fisheries management guidance. This study provides details for analyzing the composite (i.e. age-aggregated or stage-structured) yield per recruit (CYPR) model CYPR14, and proposes CYPR14 as a management tool for tropical fisheries. The fishing mortality rates maximizing CYPR (FCYPR) and associated with the marginal increase in CYPR (F0.1) and a target composite spawning potential ratio (CSPR; F35%CSPR or F40%CSPR) were suggested as candidate fishing mortality targets, provided assessments employ the delay-differential model underlying CYPR14. Using Monte Carlo (MC) simulations relying on growth parameters and natural mortality of Lake Tanganyika's Lates stappersii and Lake Victoria's Lates niloticus, CYPR14 analyses involving maximum survivorship or declining survivorship were carried out to show how FCYPR, F0.1, F35%CSPR, and F40%CSPR could be generated, given an age of knife-edge recruitment (r). Baseline MC employed r = 1 year and yielded mean annual rates of FCYPR = 0.52, F0.1 = 0.33, and F35%CSPR = 0.51 for L. stappersii and FCYPR = 0.23, F0.1 = 0.14, and F40%CSPR = 0.16 for L. niloticus. CYPR14 with maximum survivorship produced CYPR isopleths such that the CYPR maximized at an infinite r and finite, higher F. For CYPR14 involving a declining survivorship, the CYPR declined with increased r and maximized with innermost closed-loop contours at lower F and an optimal age. The CSPR isopleths from both types of CYPR14 analyses were first concave down, and the optimal age served as their inflection point. In terms of benchmarks based on the maximum sustainable yield and of proxies thereof, CYPR14 should be for its underlying delay-differential model what the age-structured pool models are for age-structured assessment models.
Key words: Data-poor stocks / stock status / Lates stappersii / Lates niloticus / Monte Carlo simulations
© J. Munyandorero, Published by EDP Sciences 2022
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.