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Threats of Longline Fishing to Global Albatross Diversity - PubMed

  • ️Sat Jan 01 2022

Threats of Longline Fishing to Global Albatross Diversity

Gohar A Petrossian et al. Animals (Basel). 2022.

Abstract

Albatrosses are among the most threatened seabird species. Often entangled in gillnets or hooked while longline fishing gear is being set, albatrosses are affected by fishing. This is assumed to be especially true in cases where illegal longline fishing vessels are involved, as they are less likely to implement the bycatch mitigation measures implemented to reduce the risk of albatrosses being caught on their hooks. This is the assumption that was tested in the current study, which uses environmental criminology as its guiding theoretical framework. Using the spatial units of one-half-degree by one-half-degree longitude/latitude cells, this research examined the patterns of concentration of potentially illegal longlining efforts and their relationships to commercially sought-out and illegally caught (i.e., CRAAVED-concealable, removable, abundant, accessible, valuable, enjoyable, disposable) fish species concentrations, as well as their effects on the average risk of albatrosses. The results indicated that (a) potentially illegal longlining activity is spatially concentrated; (b) this concentration is exhibited in areas with the highest concentrations of the presence of CRAAVED fish; and (c) the average risk score of albatrosses, as measured by their International Union for Conservation of Nature (IUCN) Red List status, is significantly higher in the areas where illegal longlining vessels are found controlling for the activities of legal longlining vessels. These findings provide strong grounding that illegal longline fishing poses a particularly serious threat to the survival of albatrosses. These activities, however, are not randomly spread across the vast oceans, but rather are highly spatially concentrated. Therefore, the bird conservation lobby should work closely with regional fisheries management organizations to devise and implement targeted interventions aimed at reducing potential illegal longline fishing, which, in turn, will likely have positive effects on albatrosses.

Keywords: Diomedeidae; GIS; IUU; bycatch; longline fishing; policy; spatial econometrics.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1

Conceptualizing the relationship among illegal longline fishing, albatrosses, and commercially viable fish. In (a), the presence of FOC longliners is visible in the black-colored grid cells. FOC longliners tend to be in areas where there is a greater risk score of commercially viable fish, as noted by the larger graduated symbols in (b). In (c), the theoretical relationship among all three variables is visible. FOC longliners are present in areas with higher risk scores of commercially viable fish and these same areas tend to overlap with distributions of albatross species.

Figure 2
Figure 2

An example of assigning risk scores to grid cells for overlapping areas of albatross at-sea ranges. (a) Cumulative Albatross IUCN Red List Scores by Grid Cell; (b) Average Albatross IUCN Red List Scores by Grid Cell. The scores were calculated by summing the IUCN Red List status scores (0–5) of the albatross species whose at-sea ranges overlap with a given grid cell divided by the number of albatross species found within these grid cells.

Figure 3
Figure 3

The inequality of FOC longliner presence across ocean grid cells in 2016. The Lorenz line (dotted) significantly deviates from the line of equality, demonstrating that FOC longliner presence is spatially concentrated in a small number of grid cells (Gini = 0.786). More specifically, 29% of at-sea grid cells experienced the presence of at least one FOC longliner, and this 29% accounted for 100% FOC longliner presence altogether.

Figure 4
Figure 4

(a) A LISA cluster analysis of FOC longliners and (b) weighted CRAAVED fish presence. In (a) the LISA (local indicators of spatial autocorrelation) cluster map reveals a high positive autocorrelation (global Moran’s I: 0.82; p < 0.001), whereby approximately 14% of grid cells (high–high) experienced FOC longliner presence and were surrounded by grid cells experiencing similar phenomena. FOC longliner presence is significantly concentrated in certain areas, and this is hypothesized to be related to areas where there is a higher cumulative weighted risk of fish being CRAAVED. In (b), findings show a high positive autocorrelation (global Moran’s I: 0.98; p < 0.001), whereby approximately 34% of at-sea grid cells (high–high) experienced statistically significant clusters of CRAAVED fish presence. Comparing (a,b) with each other, it can be seen that FOC presence hot spots tend to overlap in CRAAVED fish hot spots, particularly in the Pacific Ocean near South America, Asia, Oceania, in the southern Atlantic Ocean, and in the Indian Ocean (r = 0.38; p < 0.001).

Figure 4
Figure 4

(a) A LISA cluster analysis of FOC longliners and (b) weighted CRAAVED fish presence. In (a) the LISA (local indicators of spatial autocorrelation) cluster map reveals a high positive autocorrelation (global Moran’s I: 0.82; p < 0.001), whereby approximately 14% of grid cells (high–high) experienced FOC longliner presence and were surrounded by grid cells experiencing similar phenomena. FOC longliner presence is significantly concentrated in certain areas, and this is hypothesized to be related to areas where there is a higher cumulative weighted risk of fish being CRAAVED. In (b), findings show a high positive autocorrelation (global Moran’s I: 0.98; p < 0.001), whereby approximately 34% of at-sea grid cells (high–high) experienced statistically significant clusters of CRAAVED fish presence. Comparing (a,b) with each other, it can be seen that FOC presence hot spots tend to overlap in CRAAVED fish hot spots, particularly in the Pacific Ocean near South America, Asia, Oceania, in the southern Atlantic Ocean, and in the Indian Ocean (r = 0.38; p < 0.001).

Figure 5
Figure 5

Endangered albatross species’ diversity within FOC longliner Areas. FOC longliners were present in 46,165 grid cells of the 159,087 at-sea grid cells in 2016. Of these 46,165 grid cells, 18% (8483 grid cells) overlapped with the ranges of at least one threatened albatross species. Such at-risk areas for IUU fishing should be the focus of prevention and bycatch mitigation strategies to reduce the mortality rates of protected albatross species.

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References

    1. Tuck G.N., Polacheck T., Bulman C.M. Spatio-temporal trends of longline fishing effort in the Southern Ocean and implications for seabird bycatch. Biol. Conserv. 2003;114:1–27. doi: 10.1016/S0006-3207(02)00378-6. - DOI
    1. Gandini P., Frere E. Spatial and temporal patterns in the by-catch of seabirds in the Argentinian long-line fishery. Fish. Bull. 2003;104:482–485.
    1. Croxall J.P., Butchart S.H.M., Lascelles B., Stattersfield A.J., Sullivan B., Symes A., Taylor P. Seabird conservation status, threats and priority actions: A global assessment. Bird Conserv. Int. 2012;22:1–34. doi: 10.1017/S0959270912000020. - DOI
    1. Huang H. By-catch of high sea long-line fisheries and measures taken by Taiwan: Actions and challenges. Mar. Policy. 2011;35:712–720. doi: 10.1016/j.marpol.2011.02.012. - DOI
    1. Gilman E. References on Seabird by-Catch in Long-Line Fisheries. Blue Ocean Institute; Honolulu, HI, USA: 2004.

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