Assesment Data

 

 

What is a fish stock?

A biological fish stock is a group of fish of the same species that live in the same geographic area and mix enough to breed with each other when mature. ‘Stock’ may also refer to a multispecies complex that is managed as a single unit.

Stock assessments are based on models of fish populations that require three primary categories of data inputs: catch, abundance, and biology. To ensure the highest quality stock assessments and the best information for resource managers, stock assessment data inputs must be accurate and timely.


 

Catch Data – The amount of fish removed from a stock by fishing

A national network of fishery monitoring programs collects catch data continuously data and makes this information available to stock assessment scientists and managers. Sources of catch data include:

• Dockside monitoring: Often conducted in partnership with state agencies and Interstate Fisheries Commissions, dockside monitors work to record commercial fisheries catch receipts in order to provide an accurate measure of commercial landings. Monitors also take biological samples of the length, sex, and age of the catch0.

• Logbooks: Records from commercial fishermen of their fishing location, gear, and catch.

• Observers: Biologists observe fishing operations on a certain proportion of fishing vessels (depending on fishery) and collect data on the amount of catch and discards, as well as biological samples. Read more on the Observer Program...

• Recreational sampling: Technicians and biologists collect information on the level of catch in recreational fisheries through telephone interview surveys and dockside sampling. Read more about Recreational Fisheries...

 

Biology Data – Information on fish growth rates, natural mortality, and reproduction

Biological data important to stock assessments includes information on fish size, age, growth rates, maturity and reproduction, and sources of mortality beyond fishing. Biological information and samples may be collected during fishery-independent surveys or by observers and other fishery sampling programs. In addition to research conducted by NOAA Fisheries scientists, academic programs, cooperative research with the fishing industry, and other NOAA partners are important sources of biological data.

Abundance Data – A measure, or relative index, of the number or weight of fish in a stock

Abundance data ideally come from fishery-independent surveys. These surveys are statistically-designed, systematic sampling that is carried out by NOAA research vessels or contracted commercial fishing vessels separate from commercial fishing operations. Surveys sample fish at many locations throughout the range of the stocks being surveyed. Most fishery-independent surveys are conducted annually to track fluctuations closely and collect data on a range of ecosystem components. Survey vessels use standardized gear and sampling methods to collect data in the same way every year, providing a relative index of abundance over time. Some surveys utilizing advanced technology can achieve an absolute calibration. In some instances, commercial catch rates can be calibrated to provide additional measures of abundance, although with a lower spatial coverage and degree of standardization than can be achieved with fishery-independent surveys.

 

How is NOAA Fisheries working to improve data collection programs?

Good stock assessments require high quality data inputs. Here are some of the things NOAA is doing to ensure we continue to provide the best available science to resource managers:

• Electronic data collection for rapid access

• Advanced monitoring equipment attached to traditional sampling gear to collect environmental data concurrently during surveys

• Visual surveys in complex (i.e. non-trawlable) habitats using imaging systems on robotic and autonomous underwater vehicles (AUVs - click here to read more about AUVs from one of our Teachers at Sea)

• Non-extractive abundance sampling using hydroacoustic technology

• Use electronic fish tags, genetic analyses, and research on the chemical composition of otoliths (fish ear bones) to better define stock boundaries, habitat use, and fish movements