Voglio sapere a riguardo di…

Federal Register / Vol. 86, No. 106 / Friday, June 4, 2021 / Proposed Rules with sufficient frequency to necessitate the establishment of required mitigation measures for multiple U.S. fisheries using both types of gear NMFS, 2014.
It is likely that no species of marine mammal can be definitively excluded from the potential for interaction with fishing gear e.g., Northridge, 1984;
however, the extent of interactions is likely dependent on the biology, ecology, and behavior of the species involved and the type, location, and nature of the fishery.
Trawl Nets As described previously, trawl nets are towed nets i.e., active fishing consisting of a cone-shaped net with a codend or bag for collecting the fish and can be designed to fish at the bottom, surface, or any other depth in the water column. Here we refer to bottom trawls and midwater trawls i.e., any net not designed to tend the bottom while fishing. Trawl nets in general have the potential to capture or entangle marine mammals, which have been known to be caught in bottom trawls, presumably when feeding on fish caught therein, and in midwater trawls, which may or may not be coincident with their feeding Northridge, 1984.
Capture or entanglement may occur whenever marine mammals are swimming near the gear, intentionally e.g., foraging or unintentionally e.g., migrating, and any animal captured in a net is at significant risk of drowning unless quickly freed. Animals can also be captured or entangled in netting or tow lines also called lazy lines other than the main body of the net; animals may become entangled around the head, body, flukes, pectoral fins, or dorsal fin.
Interaction that does not result in the immediate death of the animal by drowning can cause injury i.e., Level A
harassment or serious injury.
Constricting lines wrapped around the animal can immobilize the animal or injure it by cutting into or through blubber, muscles and bone i.e., penetrating injuries or constricting blood flow to or severing appendages.
Immobilization of the animal, if it does not result in immediate drowning, can cause internal injuries from prolonged stress and/or severe struggling and/or impede the animals ability to feed resulting in starvation or reduced fitness Andersen et al., 2008.
Marine mammal interactions with trawl nets, through capture or entanglement, are well-documented.
Dolphins are known to attend operating nets to either benefit from disturbance of the bottom or to prey on discards or fish within the net. For example, Leatherwood 1975 reported that the
VerDate Sep<11>2014

17:49 Jun 03, 2021

Jkt 253001

most frequently observed feeding pattern for bottlenose dolphins in the Gulf of Mexico involved herds following working shrimp trawlers, apparently feeding on organisms stirred up from the benthos. Bearzi and di Sciara 1997
opportunistically investigated working trawlers in the Adriatic Sea from 1990
94 and found that ten percent were accompanied by foraging bottlenose dolphins. However, midwater trawls have greater potential to capture cetaceans, because the nets may be towed at faster speeds, these trawls are more likely to target species that are important prey for marine mammals e.g., squid, mackerel, and the likelihood of working in deeper waters means that a more diverse assemblage of species could potentially be present Hall et al., 2000.
Globally, at least seventeen cetacean species are known to feed in association with trawlers and individuals of at least 25 species are documented to have been killed by trawl nets, including several large whales, porpoises, and a variety of delphinids Karpouzli and Leaper, 2004;
Hall et al., 2000; Fertl and Leatherwood, 1997; Northridge, 1991. At least eighteen species of seals and sea lions are known to have been killed in trawl nets Wickens, 1995. Generally, direct interaction between trawl nets and marine mammals both cetaceans and pinnipeds has been recorded wherever trawling and animals co-occur. Tables 8, 9, and 10 later in this document display more recent information regarding interactions specifically in U.S. fisheries and are more relevant to the development of take estimates for this proposed rule. In evaluating risk relative to a specific fishery or comparable research survey, one must consider the size of the net as well as frequency, timing, and location of deployment. These considerations inform determinations of whether interaction with marine mammals is likely. For example, in most cases, research gear employs smaller nets and shorter longlines than commercial gear.
Similarly, net soak times for research are often shorter than commercial fisheries and, in many cases, are monitored.
LonglinesLonglines are basically strings of baited hooks that are either anchored to the bottom, for targeting groundfish, or are free-floating, for targeting pelagic species and represent a passive fishing technique. Pelagic longlines, which notionally fish near the surface with the use of floats, may be deployed in such a way as to fish at different depths in the water column.
For example, deep-set longlines targeting tuna may have a target depth
PO 00000

Frm 00021

Fmt 4701

Sfmt 4702

30099

of 400 m, while a shallow-set longline targeting swordfish is set at 3090 m depth. We refer here to bottom and pelagic longlines. Any longline generally consists of a mainline from which leader lines gangions with baited hooks branch off at a specified interval, and is left to passively fish, or soak, for a set period of time before the vessel returns to retrieve the gear.
Longlines are marked by two or more floats that act as visual markers and may also carry radio beacons; aids to detection are of particular importance for pelagic longlines, which may drift a significant distance from the deployment location. Pelagic longlines are generally composed of various diameter monofilament line and are generally much longer, and with more hooks, than are bottom longlines.
Bottom longlines may be of monofilament or multifilament natural or synthetic lines.
Marine mammals may be hooked or entangled in longline gear, with interactions potentially resulting in death due to drowning, strangulation, severing of carotid arteries or the esophagus, infection, an inability to evade predators, or starvation due to an inability to catch prey Hofmeyr et al., 2002, although it is more likely that animals will survive being hooked if they are able to reach the surface to breathe. Injuries, which may include serious injury, include lacerations and puncture wounds. Animals may attempt to depredate either bait or catch, with subsequent hooking, or may become accidentally entangled. As described for trawls, entanglement can lead to constricting lines wrapped around the animals and/or immobilization, and even if entangling materials are removed the wounds caused may continue to weaken the animal or allow further infection Hofmeyr et al., 2002. Large whales may become entangled in a longline and then break free with a portion of gear trailing, resulting in alteration of swimming energetics due to drag and ultimate loss of fitness and potential mortality Andersen et al., 2008. Weight of the gear can cause entangling lines to further constrict and further injure the animal. Hooking injuries and ingested gear are most common in small cetaceans and pinnipeds but have been observed in large cetaceans e.g., sperm whales. The severity of the injury depends on the species, whether ingested gear includes hooks, whether the gear works its way into the gastrointestinal GI tract, whether the gear penetrates the GI
lining, and the location of the hooking e.g., embedded in the animals stomach
E:FRFM04JNP2.SGM

04JNP2