Set unwanted catch quotas

Overall effectiveness category Awaiting assessment
Number of studies: 1
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Background information and definitions

Fishing can impact reptiles by catching individuals unintentionally or causing injury or death through entanglements in fishing gear. Unwanted catch (‘bycatch’) quotas are used to set catch limits for unwanted species. When the quota for a particular species is reached, the fishery may be closed to all forms of fishing likely to catch that species. This may reduce the pressure on populations of reptiles that are caught accidentally and allow time for populations to recover.

Study locations

Key messages

One study evaluated the effects of setting unwanted catch quotas on reptile populations. This study was in the USA.

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (1 STUDY)

Survival (1 study): One study in the USA found that following the re-opening of a swordfish long-line fishery with turtle catch limits in place, loggerhead turtle bycatch reached the annual catch limit in two of three years, and when the limit was reached the fishery was closed for the rest of the year.

BEHAVIOUR (0 STUDIES)

About key messages

Key messages provide a descriptive index to studies we have found that test this intervention.

Studies are not directly comparable or of equal value. When making decisions based on this evidence, you should consider factors such as study size, study design, reported metrics and relevance of the study to your situation, rather than simply counting the number of studies that support a particular interpretation.

Supporting evidence from individual studies

A study in 2005–2007 in pelagic waters north of Hawaii, USA (Howell et al. 2008) found that after an annual unwanted catch quota was established for loggerhead turtles Caretta caretta in a swordfish Xiphias gladius shallow-set longline fishery, turtle catch reached the limit in the second year after the fishery re-opened with catch limits, but was lower in the first and third year. Results were not statistically tested. In the first year after the fishery re-opened with a turtle catch limit, nine loggerhead turtles (0.004–0.049 turtles/1,000 hooks) were caught, but in the second year the catch limit of 17 turtles (0.013–0.044 turtles/1000 hooks) was reached and the fishery was closed for the rest of the year. In the third year, 12 turtles were caught (0.0–0.028 turtles/1,000 hooks). In late 2004, the fishery re-opened after a two-year shut down due the high number of loggerhead turtle catch levels. After re-opening, a catch limit of 17 turtles/year was established, after which the fishery would close for the rest of the year. In January–March 2005–2007, line deployments (2005: 520; 2006: 842; 2007: 797), hooks put out (2005: 429,580; 2006: 670,914; 2007: 689,486), and loggerhead turtle interactions were monitored. In January–March 2007, fishers were also provided daily information in electronic and paper format from a ‘TurtleWatch’ tool that recommended areas to avoid to reduce turtle interactions (see original paper).
Study and other actions tested
Referenced paper
Howell E.A., Kobayashi D.R., Parker D.M., Balazs G.H. & Polovina J.J. (2008) TurtleWatch: a tool to aid in the bycatch reduction of loggerhead turtles Caretta caretta in the Hawaii-based pelagic longline fishery. Endangered Species Research, 5, 267-278.

Please cite as:

Sainsbury K.A., Morgan W.H., Watson M., Rotem G., Bouskila A., Smith R.K. & Sutherland W.J. (2021) Reptile Conservation: Global Evidence for the Effects of Interventions for reptiles. Conservation Evidence Series Synopsis. University of Cambridge, Cambridge, UK.

Where has this evidence come from?

List of journals searched by synopsis

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This Action forms part of the Action Synopsis:

Reptile Conservation

Related Actions

Actions	Effectiveness	Studies	Category
Limit the length of fishing gear or density of traps in an area Action Link	No evidence found (no assessment)	0	Synopsis Link
Set unwanted catch quotas Action Link	Awaiting assessment	1	Synopsis Link
Limit the number of fishing vessels or fishing days in an area Action Link	No evidence found (no assessment)	0	Synopsis Link