Limit, cease or prohibit commercial fishing

Overall effectiveness category Evidence not assessed
Number of studies: 1
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Effectiveness
not assessed
Certainty
not assessed
Harms
not assessed

Calculating overall effectiveness category

Background information and definitions

Overexploitation through commercial fishing is a major threat facing anguillid eel populations (Kaifu et al. 2019, Williamson et al. 2023). Ceasing or prohibiting all commercial fishing in an area may significantly reduce overall fishing pressure to levels that may allow commercially targeted eel populations to recover. The impacts of commercial fishing may also be reduced by restricting fishing activities in specific areas or during particular times (e.g., when species are more vulnerable). This could involve limiting the number of fishing vessels or fishing days in an area, limiting the number/size of lines, nets or traps used, setting catch quotas or introducing fishing permits or licenses.

^{Kaifu K., Stein K., Dekker W., Walker N., Dolloff A.C., Steele K., Aguirre A.A., Nijman V., Siriwat P. & Sasal P. (2019) Global exploitation of freshwater eels (genus Anguilla). Pages 376–422 in: Coulson P. & Don A. (eds.) Eel Biology, Monitoring, Management, Culture and Exploitation: Proceedings of the First International Eel Science Symposium, 5M Publishing, Sheffield. https://doi.org/10.1079/9781800629097.0023}

^{Williamson M.J., Pike C., Gollock M., Jacoby D.M. & Piper A.T. (2023) Anguillid eels. Current Biology, 33, R888–R893. https://doi.org/10.1016/j.cub.2023.07.044}

Study locations

Key messages

One study evaluated the effects of limiting, ceasing or prohibiting commercial fishing on anguillid eel populations in inland habitats. The study was in Ireland.

COMMUNITY RESPONSE (0 STUDIES)

POPULATION RESPONSE (1 STUDY)

Abundance (1 study): One before-and-after study in Ireland found that the amount of silver European eel recaptured in a river was similar before and three years after ceasing commercial fishing practices.

Condition (1 study): One before-and-after study in Ireland found that the average length of female silver European eels in a river was similar before and three years after ceasing commercial fishing practices.

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 before-and-after study in 2008–2011 in a river in Ireland (MacNamara et al. 2014) reported that, three years after ceasing commercial fishing practices in summer months, total catch and recapture rates of silver European eels Anguilla anguilla and average length of female eels were similar to before. Unless stated, Results are not based on tests of statistical significance. In the year before commercial fishing ceased, 10,472 kg of silver eels were caught (average female length: 531–632 mm) compared to 10,712–15,452 kg of silver eels (average female length: 534–646 mm) in the three years after. Annual recapture rates of silver eels did not differ significantly between all four years (one year before: 151 eels, 24%, over three years after: 95–142 eels, 21–25%). An Eel Management Plan required the closure of a yellow eel fishery in the River Shannon in 2009, ceasing longline and fyke net fishing in summer months. In 2008–2011, silver eels were captured in up to 20 stow nets at an eel weir located 3–11 km upstream of a hydropower dam. Some captured eels (568–635 eels/year) were tagged with T-bar anchor tags and released roughly 200 m upstream of the weir. In 2008 (before fishing ceased), 1,867 female eels were measured during 25 sampling occasions. In 2009–2011 (after summer fishing ceased), 785–1,291 female eels were measured on 8–10 occasions.
Study and other actions tested
Referenced paper
MacNamara R. & McCarthy T.K. (2014) Silver eel (Anguilla anguilla) population dynamics and production in the River Shannon, Ireland. Ecology of Freshwater Fish, 23, 181-192.

Please cite as:

Cutts V., Berthinussen A., Reynolds S.A., Clarhäll A., Land M., Smith R.K. & Sutherland W.J. (2024) Eel Conservation in Inland Habitats: Global evidence for the effects of actions to conserve anguillid eels. Conservation Evidence Series Synopses. University of Cambridge, Cambridge, UK.