Unanswered Forum Topics
Field Study 756
Field Study 758
Field Study 758
Decreased feeding ability of a minke whale (Balaenoptera acutorostrata) with entanglement-like injuries
This investigation details an unusual encounter with a lunge-feeding minke whale with fresh entanglement-like injuries to its head and ventral pouch. It also discusses results from a short-term comparative study that tested whether the whale fed differently than five uninjured minke whales feeding in the same area. Collectively, this study: 1) quantifies how much a rope-like injury can restrict the expansion of a minke's ventral pouch while feeding, 2) provides the first minke whale lunge-feeding velocities from a photogrammetric method using digital video, and 3) describes a ne
Field Study 760
Field Study 760
Interactions of Patagonian toothfish fisheries with killer and sperm whales in the Crozet Islands exclusive economic zone: an assessment of depredation levels and insights on possible mitigation strategies
The Patagonian toothfish longline fishery has high levels of depredation by killer and sperm whales, which puts the whales at risk of being bycatch. Observations from 2003 to 2008 revealed significant variations of interaction rates with killer whales between vessels, suggesting the influence of operational factors on vessel interaction and depredation. When killer whales were absent at the beginning of the line hauling process, short lines (<5,000 m) provided higher yield and were significantly less impacted by depredation than longer lines.
Field Study
Field Study
Field Study
Field Study
Whale Shark
Historically, the whale shark has been hunted for its meat and liver oil. Whale shark fins are considered inferior in quality and the species is generally not targeted for its fins, although a market for them does exist in Asia due to their massive size (Norman 2005). Despite the fact that there is a paucity of data regarding whale shark bycatch, it is believed that the species most commonly becomes entangled in purse seines, longlines, and gillnets, particularly set nets.
Thorny skate
Data from the Northwest Atlantic suggests that the thorny skate began declining in the early 1980s and accelerated in the early 1990s (Burgess et al 2005). In US waters, dredging for scallops also poses a risk (Packer et al 2003). Additionally, a targeted fishery for the species emerged in Canada in order to meet a growing European demand for skate wings (Kulka et al 2009). Bycatch in Canadian waters occurs on the Scotian Shelf, though landings do not equal those of the targeted fishery (Kulka et al 2009).
Lanthanide metals as potential shark deterrents
Australian sea lion
The Australian sea lion population decreased due to harvests in the 17th and 18th centuries and traditional subsistence hunting by aborigines (Goldsworhty & Gales 2008). Isolated reports of deliberate killings have persisted into the 21st century as well (DEWHA 2010). Although the species is now protected by Australian law throughout its range, recovery towards pre-sealing levels has been minimal (Goldsworthy and Gales 2008; AFMA 2010).
Study on the methods to mitigate the bycatch of juvenile bigeye tuna by introducing Double-FADs with light stimulus for tuna purse seine fishery in the Western and Central Pacific Ocean
A Double-FAD design was tested for it's ability to mitigate the incidental capture of bigeye tuna in purse fisheries of the Western and Central Pacific Ocean. The design consisted of two separate FADs with underwater light stimuli attached. The number of animals caught was not large enough to conduct statistical analyses, but based on the weight of fish, the size proportion of skipjack, yellowfin and bigeye was bigger using the Double-FAD design comapared to the normal design.