Species 2 Unrated

[Placido Teofilo]

Femalemonkfish grow larger and live longer than males; females live to at least 13 years old, growing over four feet long, and are able to reproduce at 16 inches in length. Male monkfish, however, live to seven years old, grow up to three feet in length, and are able to reproduce at 14 inches in length. Monkfish migrate seasonally to spawn and feed, spawning from February to October. They travel slowly by swimming or by using their wing-like pectoral fins to walk along the ocean floor or to ride currents.

Female monkfish release large egg veils containing more than one million eggs. The veil floats near the surface with the current until it disintegrates and the larvae hatch. The larvae feed on zooplankton, and the juveniles eat small fish, shrimp, and squid. Adult monkfish eat fish, including other monkfish, as well as crustaceans, mollusks, seabirds, and diving ducks. Overall, monkfish are opportunistic feeders, eating the most available prey at the time. Monkfish hunt by ambushing their prey, using a modified spine on their head as a fishing pole to bait and lure them to their mouths. Once the prey is close, the monkfish sucks them into their mouth, trapping them behind rows of backwards-pointing teeth. While most predacious fish such as swordfish, sharks, and thorny skate preys upon small monkfish, larger monkfish have few predators.

Increased water temperatures due to climate change is likely to affect the distribution and stock size of monkfish by expanding the breadth of suitable habitat. Spawning timing and location, development of larvae, and availability of prey species may also be affected. Improving knowledge on the influence of temperature change on monkfish populations serves as the basis for assessing the future of monkfish.

The Monkfish Fishery Management Plan includes a number of measures aimed at rebuilding monkfish populations and has been successful in allowing both northern and southern stocks to rise above target levels where the stocks are neither overfished nor is overfishing occurring. Among the management measures the Plan includes are:

Also included in the Monkfish Fishery Management Plan are measures to reduce bycatch. The Plan limits the amount of bycatch of other fish species by setting possession and landing limits and annual quotas specified in fisheries for those species. Additionally, the Plan mandates that all mesh used by gillnetters and trawlers be larger than the established minimum size to reduce to bycatch. In the Mid-Atlantic, management measures prohibit gillnetters from using large mesh (7 inches or greater) in some areas during certain times of the year to protect migrating sea turtles. Fishing closures are also timed based on projected sea surface temperatures to avoid incidental catch of sea turtles.

Monkfish, a deep-water species found along the Atlantic coast of the U.S. and Canada, have characteristics including slow growth and dense aggregation that make them vulnerable to fishing pressure. Following increased demand in the 1980s and 1990s, monkfish were found to be overfished in 1999. Fishery managers implemented a rebuilding plan and in 2008, monkfish was declared rebuilt. Stock assessments done in 2013 showed that monkfish is not overfished or subject to overfishing, according to the U.S. National Marine Fisheries Service.

Monkfish are caught with either bottom gillnets or bottom trawls. While bottom trawls and gillnets can have a significant impact on seafloor habitat, the gear used to catch monkfish operates in muddy and sandy areas that tend to be resilient to disturbance.

The monkfish fishery has bycatch that has included protected species such as sea turtles, large whales, harbor porpoises and Atlantic sturgeon, according to the U.S. National Marine Fisheries Service. Bycatch primarily occurs through entanglements with gillnets, but strict measures are being taken to reduce the risk. Some intsitutes report that it is often is difficult to attribute gillnet deaths of marine animals and turtles to a particular fishery.

Monkfish fishery management measures include area closures, area restrictions, annual catch limits, minimum harvest size and gear requirements such as limits on large-mesh gillnets. The Monterey Bay Aquarium reports that total allowable catches have been frequently exceeded in the past, although the fishery has been improving on that in recent years. The monkfish fishery previously had an "Avoid (red)" rating from the Monterey Bay Aquarium but management actions and changes to the biomass targets helped that change to a "Good Alternative (yellow)" rating in 2012.

FishChoice, Inc. (FCI) is a registered 501(c)(3) environmental nonprofit founded in 2008 that envisions a thriving and sustainable global seafood industry. FishChoice is dedicated to powering progress on seafood sustainability by giving thousands of businesses the information they need to turn commitments into action. Learn more.

This intervention involves harvesting or cutting part of a crop field or pasture, often by leaving uncut strips. In pasture, fodder or perennial crops, these strips may be harvested later in a rotation system. The uncut areas provide a refuge for predators from harvesting itself, as well as providing habitat once the rest of the field is cut. This maintains predator populations and enables them to recolonise the following crop.

Natural enemies: We found eight studies from Australia, Germany, Hungary, New Zealand, Switzerland and the USA that tested leaving part of the crop or pasture unharvested or unmown. Three (including one replicated, controlled trial) found an increase in abundance of predatory insects or spiders in the crop field or pasture that was partly uncut, while four (including three replicated, controlled trials) found more predators in the unharvested or unmown area itself. Two studies (one replicated and controlled) found that the ratio of predators to pests was higher in partially cut plots and one replicated, controlled study found the same result in the uncut area. Two replicated, controlled studies found differing effects between species or groups of natural enemies.

Predation and parasitism: One replicated, controlled study from Australia found an increase in predation and parasitism rates of pest eggs in unharvested strips.

Pests: Two studies (including one replicated, controlled study) found a decrease in pest numbers in partially cut plots, one of them only for one species out of two. Two studies (one replicated, the other controlled) found an increase in pest numbers in partially cut plots, and two studies (including one replicated, controlled study) found more pests in uncut areas.

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.

A controlled study in 1972 of two 16.1 ha alfalfa Medicago sativa fields in California, USA (Summers 1976) found that predator and pest numbers were higher in the field with uncut strips than the completely cut field. There were 18,044 individual predators and 16,138 pest (lygus bugs Lygus spp. and pea aphids Acyrthosiphon pisum) individuals in the field with uncut strips and 7,131 predators and 12,557 pests in the completely cut field. Predators included spiders (Araneae), damsel bugs Nabis spp., green lacewing Chrysoperla (Chrysopa) carnea and ladybirds (Coccinellidae). Lygus bugs moved from uncut strips into cut areas, but moved back to uncut strips when cutting occurred. Predatory species showed a similar pattern. Alfalfa hay protein content was slightly higher in the field with uncut strips (18.1-20.7% protein) than the completely cut field (17.1-18.2%) but modified crude protein was slightly lower. One field had banks 1 m-wide and 0.2 m high distributed every 15-25 m. At each mowing period, banks were cut alternately (one alfalfa strip left uncut at every alternate raised strip, the next bank cut). Cuttings were distributed either side of the strip. Invertebrates were sampled on uncut and cut strips and between strips (10 samples/location) using a D-vac suction sampler. The second field was cut completely, and sampled using the same method as in the field with cut strips. Sampling took place one week after strip-cutting began (after the second cut, 7th May) and continued bimonthly until mid-September.

A controlled trial from 1978-1980 at Pukekohe, New Zealand (Cameron et al. 1983) found a higher ratio of predators to aphids Acyrthosiphon spp. in five out of seven periods in a plot where strips of alfalfa Medicago sativa were left uncut than in a fully cut plot. The plot with uncut strips had fewer aphid outbreaks (two aphid outbreaks in seven interharvest periods) than a fully cut plot (four aphid outbreaks). Peak aphid numbers on alfalfa stems were also higher in the fully cut plot (5.5-400.3 aphids/stem) than the plot with uncut strips (0.6-124.6 aphids/stem). Two 40 x 60 m plots were compared: one continuously-cut plot and one strip-cut plot. In the strip-cut plot, two 10 m-wide strips were cut when the continuously-cut plot was mown, the remaining two strips were cut when the previously cut strips were half-grown. Aphids were sampled by sweep netting (50 sweeps/plot) and counting aphids on 10 alfalfa stems at six points along one transect/plot.

A replicated, controlled trial in 1997-1998 in a 4 ha alfalfa Medicago sativa field with strip- and conventional-harvesting in New South Wales, Australia (Hossain et al. 2001) found that predation and parasitism of Helicoverpa spp. (pest) eggs was higher in unharvested (36.7% eggs predated, 3.31% parasitised) than harvested strips (21.7% eggs predated, 0.85% parasitised). Total predator abundance (spiders (Araneae), red and blue beetles Dicranolaius bellulus and transverse ladybird Coccinella transversalis) was higher in the strip-harvested area (average 5.1-9.1 predators/0.4 m) than the conventionally-cut area (1.2-7.6), and higher in unharvested than harvested strips. Helicoverpa spp. was less abundant in the strip- than conventionally-harvested area (0.1-9.2 individuals/0.4 m vs. 0.7-27.6) but another pest, lucerne leaf roller Merophyas divulsana had similar numbers in both treatments (0.3-18.4 vs. 0.1-19.0); both pests were more abundant in unharvested than harvested strips. There were eight 200 x 14 m strips, split lengthways; one half cut a week before normal harvesting (harvested strip), one half cut two weeks later (unharvested strip). Subsequently, strips were cut when 10% alfalfa was flowering. Strips were vacuum-sampled five times. Helicoverpa spp. eggs were placed in strips to assess predation and parasitism rates. The 112 x 158 m conventionally-harvested block was cut three times, with three vacuum samples.

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