Foraging strategies of shy albatross Thalassarche cauta breeding at Albatross Island, Tasmania, Australia

Hedd, April; Gales, Rosemary; Brothers, Nigel

doi:10.3354/meps224267

Cited by 60 publications

(40 citation statements)

References 27 publications

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“…Even though most results in our study were recorded during incubation, when trips of seabirds are normally longer than during the chick rearing stage (Morris and Black, 1980;Hedd et al, 2001), longer foraging trips probably indicated a relatively low food availability that lasted up to the end of the breeding season (see also similar results in Morris and Black, 1980;Bukacinska et al, 1996). Breeding success in 1998 was actually the lowest since 1991 (Genovart et al, 2003), when the trawling moratorium was first established, and significantly lower than those recorded during the study of (χ 2 =81.92, p < 0.0001).…”

Section: Discussionsupporting

confidence: 54%

“…In the western Mediterranean, this resource is also very predictable both in space and time, especially for trawlers, which always operate in the same fishing grounds off the harbours and in the same timetables (Martín, 1989;Oro, 1995a;Martínez-Abraín et al, 2002). This factor probably enhances the learning of feeding locations, increasing foraging efficiency (see also Becker et al, 1993;Irons, 1998;Hamer et al, 2001;Hedd et al, 2001). Nevertheless, even when the main foraging resource was available (i.e.…”

Section: Discussionmentioning

confidence: 99%

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Activity patterns and foraging behaviour of Audouin' s gulls in the Ebro Delta, NW Mediterranean

2004

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SUMMARY: Twenty Audouin's gulls, Larus audouinii, breeding in the Ebro Delta (NW Mediterranean) were radio-tracked in 1998 to study their foraging behaviour and activity patterns. Some detrimental effects of tagging on the breeding success of the birds were detected, especially when both members of the pair were tagged. The results were actually constrained by the low number of locations due to natural breeding failure and failure in tag emission, as well as the adverse effect of tagging. However, through a combination of aircraft surveys at sea and a fixed station for automatic tracking of the presence of the birds at the colony, novel individual-based information of home ranges and activity patterns was obtained. Trawler fishing activity seemed to influence both the foraging range and habitat use: while trawlers operated, gulls overlapped their fishing grounds with vessels, probably to scavenge on discards. Very few locations were obtained during a trawling moratorium period, although they were all recorded in coastal bays and terrestrial habitats. During the trawling activity period, gulls ranged over a minimum convex polygon area of 2900 km 2 . Gulls were tracked up to 40 km from the colony, but some individuals were observed beyond 150 km while still breeding. Arrivals and departures from the colony were in accordance with the trawling timetable. However, most birds also showed some nocturnal foraging activity, probably linked to active fishing of clupeoids (following diel migrations) or to the exploitation of purse-seine fishing activity. Foraging trips lasted on average 15 hours: males performed significantly shorter trips than females, which spent more time outside the colony. The proportion of nocturnal time involved in the foraging trips was the same for males and females, but whilst all males initiated their trips both during the day and at night, some females only initiated their trips during the day. Hatching success was found to be related to foraging effort by males. Gulls spent on average ca. 38% of their time budget outside the nesting territory, representing the time devoted mainly to flying, foraging and other activities.Key Words: radiotracking, trawler fisheries, activity patterns, seabird, foraging range RESUMEN: PATRONES DE ACTIVIDAD Y COMPORTAMIENTO DE CAZA EN LA GAVIOTA DE AUDOUIN EN EL DELTA DEL EBRO, MEDITERRÁNEO OCCIDENTAL. -El comportamiento de forrajeo de la gaviota de Audouin Larus audouinii y sus patrones de actividad fueron estudiados en la colonia del delta del Ebro (Mediterráneo noroccidental) mediante el marcaje con radioemisores. Detectamos algunos efectos negativos en la fecundidad de los individuos marcados, especialmente cuando los dos miembros de la pareja portaban radio-emisores. De hecho, los resultados estuvieron limitados por el bajo número de localizaciones debido a los fallos de señal de muchos de los emisores, los fracasos reproductivos y los efectos adversos del marcaje. La actividad de la flota de arrastre pareció influir tanto sobre el área de forrajeo como sobr...

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Section: Discussionsupporting

confidence: 54%

Section: Discussionmentioning

confidence: 99%

Activity patterns and foraging behaviour of Audouin' s gulls in the Ebro Delta, NW Mediterranean

2004

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“…Thus, sexual segregation by water depth in diving birds could be related to size dimorphism (Williams 1991;Kato et al 2000). In addition, satellite tracking has revealed largescale sex-related differences in foraging areas during the breeding season in some (González-Solís et al 2000;Nel et al 2002), but by no means all, procellariiform seabirds (Anderson et al 1998;Stahl & Sagar 2000b;Hedd et al 2001). Detection of such macrohabitat selection is not straightforward, however, as overall foraging ranges of males and females may overlap considerably, and even if there are apparent differences in core areas (e.g.…”

Section: Introductionmentioning

confidence: 99%

Seasonal sexual segregation in twoThalassarchealbatross species: competitive exclusion, reproductive role specialization or foraging niche divergence?

Phillips

Silk

Phalan

et al. 2004

Proc. R. Soc. Lond. B

277

280

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Sexual segregation by micro-or macrohabitat is common in birds, and usually attributed to size-mediated dominance and exclusion of females by larger males, trophic niche divergence or reproductive role specialization. Our study of black-browed albatrosses, Thalassarche melanophrys, and grey-headed albatrosses, T. chrysostoma, revealed an exceptional degree of sexual segregation during incubation, with largely mutually exclusive core foraging ranges for each sex in both species. Spatial segregation was not apparent during brood-guard or post-guard chick rearing, when adults are constrained to feed close to colonies, providing no evidence for dominance-related competitive exclusion at the macrohabitat level. A comprehensive morphometric comparison indicated considerable species and sexual dimorphism in wing area and wing loading that corresponded, both within and between species, to broad-scale habitat preferences relating to wind strength. We suggest that seasonal sexual segregation in these two species is attributable to niche divergence mediated by differences in flight performance. Such sexual segregation may also have implications for conservation in relation to sex-specific overlap with commercial fisheries.

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“…Little can be made of this considering that of the 9 shots in which interactions were observed on that vessel, only 2 were while fishing at depths ≥200 m, but it is consistent with the known behaviour of shy albatross, which have an overwhelming tendency to restrict their foraging to shelf waters (e.g. Hedd et al 2001, Alderman et al 2010. However, while fishing depths reported during this study ranged between 55 and 510 m, observations during this study found no influence of fishing depth on seabird abundance.…”

Section: Seabird Interact Ionsmentioning

confidence: 66%

Industry-based development of effective new seabird mitigation devices in the southern Australian trawl fisheries

Koopman¹,

Boag²,

Tuck³

et al. 2018

Endang. Species. Res.

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Incidental mortality of seabirds caused by interactions with the warp wires of trawl vessels in Australia's Commonwealth-managed Southern and Eastern Scalefish and Shark Fishery has been reported by on-board observers. Seabird mortality as a result of fishery interactions is an issue of global conservation concern. This paper describes an industry-led study that developed and tested the effectiveness of 2 experimental mitigation devices for trawl vessels: a baffler and a water sprayer. These were tested against a control which was previously the only prescribed device (a warp deflector called a pinkie). Seabird interactions were observed during 69 shots comparing the sprayer against the control, and 55 shots comparing the baffler against the control. The seabird mitigation device employed alternated between the trial device (either the water sprayer or baffler) and the control device. Both experimental mitigation devices showed significant reductions in heavy interaction rates (interactions per shot) compared with the pinkie (83.7 and 58.9%). On stern trawlers, both new devices are deployed at the start of fishing and retrieved at the end of fishing operations, whereas pinkies need to be deployed and retrieved for each shot. This results in time savings and reduced risks to crew. Based on the findings from this study, the Australian Fisheries Management Authority now allows vessels to meet seabird bycatch mitigation requirements through use of either new device. The outcomes of this research and subsequent uptake of the new mitigation devices will greatly contribute to the reduction of incidental fishing mortality in Australian, and potentially other trawl fisheries.

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Foraging strategies of shy albatross Thalassarche cauta breeding at Albatross Island, Tasmania, Australia

Cited by 60 publications

References 27 publications

Activity patterns and foraging behaviour of Audouin' s gulls in the Ebro Delta, NW Mediterranean

Activity patterns and foraging behaviour of Audouin' s gulls in the Ebro Delta, NW Mediterranean

Seasonal sexual segregation in twoThalassarchealbatross species: competitive exclusion, reproductive role specialization or foraging niche divergence?

Industry-based development of effective new seabird mitigation devices in the southern Australian trawl fisheries

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