Presence-Absence Sampling for Fisheries Management

It is often important to estimate the abundance of a fish stock when the stock is somewhat depleted. For pelagic species this presents great operational difficulties, because adult surveys may be prohibitively expensive and time consuming. Here we introduce a method for estimating the spawning biomass of a stock by means of egg or larval surveys. In particular, we develop a series of models for presence-absence sampling of eggs or larvae and show how presence-absence data can be used to estimate adult spawning biomass. The models are based on an underlying probabilistic description of the aggregation of eggs or larvae, a search process, and a description of habitat structure. Methodologies are given for estimating the distribution of the size of the spawning biomass from presence-absence data. A case study of sardine is used to justify a number of the assumptions. The methods are applied to a 1985 survey for sardine eggs and are compared to an alternative method based on egg production.

Download Full-text

Science for integrative management of a diadromous fish stock: interdependencies of fisheries, flow, and habitat restoration

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2020-0075 ◽

2020 ◽

Vol 77 (9) ◽

pp. 1487-1504 ◽

Cited By ~ 1

Author(s):

Stuart H. Munsch ◽

Correigh M. Greene ◽

Rachel C. Johnson ◽

William H. Satterthwaite ◽

Hiroo Imaki ◽

...

Keyword(s):

Fisheries Management ◽

Habitat Restoration ◽

Central Valley ◽

Monitoring Data ◽

Juvenile Salmon ◽

Fish Stock ◽

Flow Management ◽

Anthropogenic Stressors ◽

Natural Productivity

Fish face many anthropogenic stressors. Authorities in marine, estuarine, and freshwater realms often share interdependent fisheries management goals, but address singular stressors independently. Here, we present a case study suggesting that coordinating stressor relief across management realms may synergize conservation efforts, especially to actualize restoration benefits. Major efforts are underway to restore juvenile salmon habitat across California’s Central Valley landscape, but it is unclear how fisheries and flow management will influence juvenile salmon occupancy of restored sites. Leveraging monitoring data, we find that for juvenile salmon (<55 mm) to actualize benefits of restored habitats will likely require maintaining spawner abundances and flows at or above intermediate values, especially in less-connected portions of the landscape. Furthermore, restoration efforts may prioritize more connected regions to promote use of restored areas, considering that less connected areas are often uninhabited when water and spawners are scarcer. This ecosystem-based framework that evaluates interdependencies of management decisions may be applied to realize natural productivity and enhance conservation in many systems.

Download Full-text

An Alternative Perspective on Recruitment Overfishing and Biological Reference Points

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f87-110 ◽

1987 ◽

Vol 44 (4) ◽

pp. 913-918 ◽

Cited By ~ 173

Author(s):

M. P. Sissenwine ◽

J. G. Shepherd

Keyword(s):

Fisheries Management ◽

Reference Point ◽

Reference Points ◽

Fishing Mortality ◽

Alternative Perspective ◽

Conventional Models ◽

Definition Of ◽

Yield Per Recruit ◽

Spawning Biomass

Biological reference points are used to guide fisheries management decisions. The reference points most often used are expressed in terms of fishing mortality rate (F). Fmsy relates to the maximization of sustainable yield. In principle, it is a most useful reference point, but in practice it is difficult to estimate. Fmax and F0.1 relate to certain levels of yield per recruit and are easily estimated, but they ignore conservation of the resource. Recruitment overfishing has usually been understood to occur when a population has been fished down to a point where recruitment is substantially reduced or fails. It has not been used as a basis for a biological reference point because the definition is vague and cannot be readily related to fishing mortality. Levels of spawning biomass below which recruitment seems to be reduced have been used, but their determination from available data is usually difficult and controversial. We propose an alternative definition of recruitment overfishing in terms of the level of fishing pressure that reduces the spawning biomass of a year class over its lifetime below the spawning biomass of its parents on average. Conventional models and types of data can be used to determine this level of F, denoted as Frep, which clearly relates to the replacement of spawning biomass and thus to sustainability of a population and yield in the long term.

Download Full-text

The importance of satellite-based vessel monitoring system (VMS) for fisheries management: A case study in the Portuguese trawl fleet

Maritime Engineering and Technology ◽

10.1201/b12726-7 ◽

2012 ◽

pp. 33-38 ◽

Cited By ~ 1

Keyword(s):

Monitoring System ◽

Fisheries Management

Download Full-text

Population characteristics, space use and habitat associations of the seahorse Hippocampus reidi (Teleostei: Syngnathidae)

Neotropical Ichthyology ◽

10.1590/s1679-62252007000300020 ◽

2007 ◽

Vol 5 (3) ◽

pp. 405-414 ◽

Cited By ~ 37

Author(s):

Ierecê Lucena Rosa ◽

Tacyana P. R. Oliveira ◽

André L. C. Castro ◽

Luiz E. de Souza Moraes ◽

Josias H. A. Xavier ◽

...

Keyword(s):

Habitat Structure ◽

Habitat Associations ◽

Population Characteristics ◽

Brazilian Coast ◽

Life Stages ◽

Unequal Distribution ◽

Ecological Information ◽

Spatial Use ◽

Conservation And Management

This paper provides a case study of a threatened seahorse species, Hippocampus reidi, highlighting the importance of using ecological information to assist conservation and management initiatives. Underwater visual sighting data (50 x 2m transect) gathered along the NE, SE and S portions of the Brazilian coast revealed an unequal distribution across localities, perhaps related to harvesting pressure, and a mean density of 0.026 ind.m-2. Our findings suggest some restricted spatial use by H. reidi, which was consistent with its estimated home range, and with re-sighting of specimens. Reproduction was recorded year-round, however productive peaks may exist. Components of habitat structure mostly used as anchoring points were mangrove plants, macroalgae, cnidarians, seagrass, sponges, and bryozoans. Conservation recommendations include: further characterization and mapping of habitats; assessment of availability and condition of microhabitats in selected areas, and studies on dispersal routes during initial life stages.

Download Full-text

Devolution of Powers in Sarawak: A Dynamic Process of Redesigning Territorial Governance in a Federal System

Asian Journal of Comparative Law ◽

10.1017/asjcl.2017.13 ◽

2017 ◽

Vol 12 (2) ◽

pp. 257-279

Author(s):

Andrew HARDING

Keyword(s):

Dynamic Process ◽

Federal System ◽

Alternative Method ◽

Cooperative Federalism

AbstractThis article is based on a case study of the developing process of devolution of powers in Sarawak as an aspect of the operation of cooperative federalism in Malaysia. The argument developed is that devolution can be seen and used in conjunction with and in reinforcement of federalism, rather than being simply an alternative method of decentralizing powers. The study finds that this approach may be more promising than a more confrontational approach based on arguments around the fulfilment of the original federal bargain, and is also potentially more open-ended and creative (a process rather than an event), embracing issues within the federal bargain but also issues that are not dealt with in that bargain. The study is based on a unique opportunity to canvass the views of Sarawak leaders at the iteration of the devolution process.

Download Full-text

Perbandingan Algoritma Boyer-Moore dan Brute Force pada Pencarian Kamus Besar Bahasa Indonesia Berbasis Android

BIOS : Jurnal Teknologi Informasi dan Rekayasa Komputer ◽

10.37148/bios.v1i2.13 ◽

2021 ◽

Vol 1 (2) ◽

pp. 54-60

Author(s):

Candra Irawan ◽

Mudafiq Riyan Pratama

Keyword(s):

String Matching ◽

Search Process ◽

Brute Force ◽

Text Search ◽

Matching Algorithm ◽

Running Time ◽

The Right ◽

Bahasa Indonesia ◽

Testing Criteria

String matching is an algorithm for matching a text to another text or also known as a text search. There are several algorithms that can be used for string matching, including the Boyer-Moore algorithm and the Brute Force algorithm. The Boyer-Moore algorithm is a string matching algorithm published by Robert S. Boyer and J. Strother Moore in 1977. This algorithm is considered the most efficient algorithm in general applications. The Boyer-Moore algorithm starts matching characters from the pattern on the right. While the Brute Force algorithm is an algorithm that matches a pattern with all text between 0 and n-m to find the existence of a pattern in the text. These two algorithms have different patterns in the search process. In this article, a comparative analysis of the performance of the Boyer-Moore and Brute Force algorithms is carried out in a case study of the search for the Big Indonesian Dictionary (KBBI) based on Android. The search process is carried out by searching based on words and word descriptions. The results of this study indicate that the criteria for running time, the Brute Force algorithm is faster than the Boyer-Moore algorithm with the total running time of the Brute Force algorithm is 168.3 ms in words, 6994.16 ms in word descriptions, while the Boyer-Moore algorithm for running time reached 304.7 ms on the word, 8654.77 ms on the word description. In the testing criteria based on related keywords, the two algorithms can display the same list of related keywords.

Download Full-text

A Case Study in Connecting Fisheries Management Challenges With Models and Analysis to Support Ecosystem-Based Management in the California Current Ecosystem

Frontiers in Marine Science ◽

10.3389/fmars.2021.624161 ◽

2021 ◽

Vol 8 ◽

Author(s):

Desiree Tommasi ◽

Yvonne deReynier ◽

Howard Townsend ◽

Chris J. Harvey ◽

William H. Satterthwaite ◽

...

Keyword(s):

Fisheries Management ◽

West Coast ◽

California Current ◽

Fishing Communities ◽

Target Species ◽

Ecosystem Models ◽

Protected Species ◽

Forage Species ◽

The U.S

One of the significant challenges to using information and ideas generated through ecosystem models and analyses for ecosystem-based fisheries management is the disconnect between modeling and management needs. Here we present a case study from the U.S. West Coast, the stakeholder review of NOAA’s annual ecosystem status report for the California Current Ecosystem established by the Pacific Fisheries Management Council’s Fisheries Ecosystem Plan, showcasing a process to identify management priorities that require information from ecosystem models and analyses. We then assess potential ecosystem models and analyses that could help address the identified policy concerns. We screened stakeholder comments and found 17 comments highlighting the need for ecosystem-level synthesis. Policy needs for ecosystem science included: (1) assessment of how the environment affects productivity of target species to improve forecasts of biomass and reference points required for setting harvest limits, (2) assessment of shifts in the spatial distribution of target stocks and protected species to anticipate changes in availability and the potential for interactions between target and protected species, (3) identification of trophic interactions to better assess tradeoffs in the management of forage species between the diet needs of dependent predators, the resilience of fishing communities, and maintenance of the forage species themselves, and (4) synthesis of how the environment affects efficiency and profitability in fishing communities, either directly via extreme events (e.g., storms) or indirectly via climate-driven changes in target species availability. We conclude by exemplifying an existing management process established on the U.S. West Coast that could be used to enable the structured, iterative, and interactive communication between managers, stakeholders, and modelers that is key to refining existing ecosystem models and analyses for management use.

Download Full-text