Overfishing aff inherency
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- Seabirds
- Overfishing kill lots of seabirds through bycatch and bottom trawling
- Fishing practices pose a significant threat to seabird populations
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Coral ReefsCoral reefs are disappearing because of overfishingRiegl et al 2009 (Bernhard Riegl { National Coral Reef Institute, Nova Southeastern University, Dania, Florida, USA}, Andy Bruckner { Khaled Bin Sultan Living Oceans Foundation, Landover, Maryland, USA}, Steve L. Coles{Bishop Museum, Honolulu, Hawaii, USA}, Philip Renaud{Khaled Bin Sultan Living Oceans Foundation, Landover, Maryland, USA} and Richard E. Dodge{ National Coral Reef Institute, Nova Southeastern University, Dania, Florida, USA}, Annals of the New York Academy of Sciences, Volume 1162, The Year in Ecology and Conservation Biology 2009 pages 136–186, 21 APR 2009, “Coral Reefs”, EBSCO) Overfishing and Destructive Fishing Overfishing has been well documented as a root cause of coral-reef decline (Jackson 1997; Jackson et al. 2001). Hughes (1994) saw overfishing of grazing fish (primarily parrot fishes) as a reason for a phase shift away from corals and toward fleshy macroalgae when the other major grazer, Diadema antillarum, was wiped out by a disease. It is unfortunate that coral reefs are often by necessity a primary target for fisheries since they are in truth not very productive fisheries systems (Hatcher 1997; McClanahan 2006). While algae production can be as high as in agricultural systems, the high internal demand for this production reduces the amount available for human consumption via fisheries to a mere 1%. Oceanic upwelling systems produce more than 50 times the fish biomass per unit algae as coral reefs do (McClanahan 2006). Not surprisingly, coral reefs are rapidly overfished when a hungry populace depends on them as protein source. Overfishing is a primary threat to about 60% of Caribbean coral reefs (Wilkinson 2006), but this is probably a conservative number. Almost all regions that are well studied report some degree of overfishing (Ballantine et al. 2008; Jokiel 2008; Rogers et al. 2008). The situation is similar in the Pacific, with significant overfishing reported from American Samoa (Birkeland et al. 2008) Guam and the Marianas (Richmond et al. 2008), the main Hawaiian islands, and in most other island and coastal nations. In U.S. jurisdiction, only the northwestern Hawaiian islands and the Pacific Remote Islands Area report near-pristine fish populations (Birkeland et al. 2008; Grigg et al. 2008). However, even there, some targeted species have collapsed and not regenerated yet, like the overharvest of pearl oysters on Pearl and Hermes Atoll in the early 1900s (Grigg et al. 2008). To combat overfishing, Australia declared 33% of its Great Barrier Reef Marine Park no-take areas (Day et al. 2003; Fernandez et al. 2005). This is the world's biggest no-take area, and it has already shown success by increasing fish populations. Overfishing is nothing new, since human–coral reef interactions date back at least 35,000 years (Pollnac 2007). While some consider the effects of early, preindustrial human exploitation mostly benign (Johannes 1978, 1981), others believe impacts to have been deleterious (Kirch and Hunt 1997) and potentially even responsible for the long-term degradation that eventually led to the deteriorated state of many of today's coral reefs (Jackson 1997; Jackson et al. 2001; Diamond 2005). Fitzpatrick and Donaldson (2007) provide evidence that coral-reef exploitation in Palau has over the past few thousand years led to declines in the numbers of finfish and mollusks. In the Palauan Rock Islands, as a clear sign of fishing pressure over 1400 years, the proportion of snappers and emperors found in middens declined, as did the overall size of all consumed fish (Masse et al. 2006). Signs of overharvesting in prehistoric times exist for giant clams (Tridacna sp. and Hippopus hippopus) as well as the humped conch (Strombus gibberulus). The list of overexploited species in prehistoric times is long and very similar to those of today (Fitzpatrick and Donaldson 2007). Also in the Caribbean, clear evidence of overexpoitation of coral-reef fishes exists at several Ceramic Age sites (LeFebvre 2007). The archaeological signs are a decrease in the size of exploited coral-reef species and an increase in the use of inshore and pelagic species over time (Wing 2001). Once overfished, resources may take a long time to regenerate, particularly if fishing pressure is maintained. Overfishing in the Marianas dates back to the Japanese period (1914–1944) and may have been influential in molding the current nearshore coral-reef community structure (Richmond et al. 2008). To compound the problem, Guam witnessed a further 70% reduction in coastal fisheries catch from 1985 to 1996. In response, no-take areas were established, that originally met with strong local opposition, but when finally enforced rapidly led to increases in fish stocks inside the reserves (Richmond et al. 2008), demonstrating again the efficacy of protected areas for fisheries management (Fig. 15). SeabirdsKills sea birdsOverfishing practices threaten seabird populationsSchei and Vidas in 2011 (Peter Johan and Davor, “The World Ocean in Globalisation : Climate Change, Sustainable Fisheries, Biodiversity, Shipping, Regional Issues”, Leiden : Martinus Nijhoff Publishers. 2011, EBSCO) Many seabird populations are declining rapidly and are threatened with extinction. They face a wide range of threats, both on land and at sea. At sea, the most pervasive threat is from longline, trawl and gill-net fisheries which accidentally take seabirds as bycatch. BirdLife International estimates that, worldwide, fisheries kill over 300,000 seabirds every year — including 100,000 albatrosses, which, as a group, are among the most threatened in the world. Many of the bird species adversely affected by fishing, especially albatrosses and petrels, spend most of their lives away from the breeding colonies, travelling vast distances across the ocean and, in so doing, encountering a diverse range of fleets and fisheries governance. The protection of these birds therefore calls for global solutions and international cooperation.
(Leigh S., “Reducing seabird bycatch in longline, trawl and gillnet fisheries”, Fish & Fisheries. Mar2007, Vol. 8 Issue 1, p31-56. 26p., EBSCO) Seabirds such as atbatrosses and petrels are long- lived, monogamous, have delayed maturity, high aluli survival, a long breeding life, and relatively low reproductive rates IWarham 1990: Brooke 2004). As a result of these factors. seabird populations can only Increase slowly under highly favour able enviromnental conditions unless they are at carrying capacity) IFurness 2003). Therefore, any additional factors increasing the rate of adult mortality will have a strong negative impact on population dynamics and the species as a whole (Tasker et al. 2000). Seabirds spend their rime on land and at sea, and as such are subject to anthropogenic Impacts In both environments. It Is perhaps. therefore, not surprising that nearly half of the world’s 125 petrel species and 16 of the 21 albatross species are classified as threatened third Life International 2(X)O). In New Zealand alone. Robertson et al. (2003) IdentIfied at least 50 bird species which breed only In New Zealand. or have part of their breeding populations there, that have been recorded In tlsherv Interactions worldwide. The Impact of bycatch events caused by longline fisheries received much international attention following Brothers’ 11991) estimate that 44 000 albatrosses were killed annually In the Southern Ocean by the Japanese tuna longline fishery alone. Tasker et al. 2(XX)) estimated that over 250,000 seabirds may have been killed In the Southern Ocean Patagonian toothfish lDissosiÅchus ¿Jegi rwi des. Notothenlidae) fishery between 1996 and 1999. In the salmon gillnet fishery in Prince WIIham Sound (Alaska). Wynne et aL (1991 I estimated that 1486 seabirds were killed In nets in 1990. SullIvan et aL (2006) estimated >1500 seabirds. predominantly black-browed albatross I Tlmaiasnzrdme nmeiaswpimrmis. Dlomedeldae). were killed by finfish trawlers operating In the Falkland Islands during 157 days of observer coverage in 200212003. These provide only a few examples of the levels of bycatch rates that have been recorded within the diflèrent fisheries. Incidental mortality through interactions with fisheries operations has in most cases simply been implied with the global declines of some species (CroxaLl et aL 1990: Brothers 1991: Welmerskirch et cd. 1997. 1999: L.ewison and Crowder 2003). A number of factors contribute to the problematic task of directly relating fisheries interactions with seabird population trends. First, obtaining an accurate measure of seabird bycatch is difficult because: estimates are generally based on a small number of observations and subsequently scaled to the total effort of a fishery: degrees of observer coverage I and experience) vary between and within fisheries: inability to quantll’ the bycatch rates in illegal. unregulated and unreported fisheries: and seabird capture estimates from counts of the number of birds hauled aboard are generally an underestimate of those interacting with fishing gear (Brothers 199 1: Gales et aL 1998: Gilman et al. 2(X)7). Secondly. It is difficult to determine the degree of impact that these bycatch events have on seabird populations In relation to other causes of mortalIty (e.g. predation. pollution. harvesting, disturbance and oceanographic pertubatlons) (Tasker et al. 2000: Lewison et al. 2005). Finally, life—history parameters are essential to assess the impact of mortalities on a population level: however, data such as accurate estimates of population sL do not exist for most seabird species I Wlenecke and Robertson 2002). Nevertheless, a growing number of studies assessing the Impact of fisheries bycatch on seabird populations have shown a negative effect on the growth and survival of the population (Tuck et cd. 2001: Baker and Wise 2005: Niel and Lebreton 2005). Furthermore. Tuck et cd. (2001) found that behavioural differences (spatial dynamics and life history) between wandering albatross (Dlornedtu exidans. L)iomedeldae) populations were implicated In their response to interactions with fisheries. Determlnlng the individual circumstances that lead to seabird mortalities In a fishery Is essential to desermine how future deaths can be prevented iBrothers t cd. 1999: Hache 20031. Seablrds interact differently with fisheries depending on the type of fishery and the gear used, For example. In longline fisheries. seabirds may become entangled on the line or caught on hooks. predominantly during line setting, and subsequently drown (Brothers et aL 1999). Vêth respect to trawl fisher ies. seabirds often collide with the net monitoring (net sonde cable and trawl warps. or birds become tangled in the net (whilst attempting to feed) when it Is at the surface during setting and hauling (Welmerskìrch et tl. 2(XXi Barton 2002: Whenecke and Robertson 2002: 1 looper et cd. 2003). In gillnet fisheries. seablrds are most often caught in the nets when diving for prey (Melvin et aI. 1999). Even within each of these lL%herles longiine. trawl and glllnet). there are other factors influencing the degree of seabird interactions. including: fishing practice, configuration of gear (pelagic or demersal). weather conditions and the seabird aemblage present (Gihuan et al. 200S). Fishing practices pose a significant threat to seabird populationsPolidoro et al 2011 (Beth A., UCN Species Programme/Conservation International Global Marine Species Assessment, Biological Sciences, Old Dominion University, Norfolk, Cristiane T. Elfes, IUCN Species Programme/Conservation International, Biodiversity Assessment Unit, Jonnell C. Sanciangco, UCN Species Programme/Conservation International Global Marine Species Assessment, Biological Sciences, Old Dominion University, Helen Pippard, IUCN Regional Office for Oceania, Kent E. Carpenter, IUCN Species Programme/Conservation International Global Marine Species Assessment, Biological Sciences, Old Dominion University, “Conservation Status ofMarine Biodiversity in Oceania: An Analysis of Marine Species on the IUCN Red List of Threatened Species.”, Journal of Marine Biology. 2011, Vol. 2011, p1-14. 14p. 1 Chart, 4 Maps, p 6-7, EBSCO) Twenty-three percent (11 of 47 species) of all sea birds in Oceania are in threatened categories. Major threats to seabirds across the globe include mortality in long-line fisheries and gill-nets, oil spills, and the impact of invasive species such as rodents and cats at breeding colonies. Additional threats to breeding sites of seabirds are habitat loss and degradation from coastal development, logging, and pollution 1591. In Nauru and Tonga, seabirds have traditionally been caught for food, but it is unclear whether this constitutes a threat (601. Some sea bird species are vulnerable to by-catch, usually in longline fisheries in the Oceania region. The most common species caught are albatrosses, petrels. shearwaters, and fulmars (611. Many of these occur only in passage through Oceania and are typically more abundant in temperate areas. However, for those species that are endemic, even infrequent fisheries-related mortality may have a significant effect on populations (61j. Very little information is available on the numbers and species of sea birds that are by-caught (62). Globally, albatrosses are one of the most threatened families of birds, and both species found in Oceania are listed as Vulnerable. Five of the six Oceania endemic sea birds Little White Tern (Gygis microrhyn cha). White-throated Storm Petrel (Nesofregetta fuliginosa), Fiji Petrel (Psei,dobulweria macgillivrayi), Henderson Petrel (Pterodrorna atrata), Collared Petrel (Pterodronia brevipes), and the Hawaiian Petrel (Pierodrorna sandwichensis) are in threatened or Near Threatened categories. These species have restricted ranges and their nesting sites are threatened by introduced species such as rats, pigs. mongoose, and feral cats. The Fiji petrel, listed as Critically Endangered, is the most threatened sea bird in the region, with the remaining population estimated to be less than 50 individuals [63). ImpactLess birds means decrease pollination, causes biodiversity extinction Rockets 6 (Rusty, Head writer for Scienceagogo.com, January 20, http://www.scienceagogo.com/news/pollinators.shtml) Biologists who have just concluded analyzing years of detailed and painstaking observations of flora and fauna have released alarming findings concerning the likely future of biodiversity on our planet. The findings show a widespread decrease in pollinators such as birds, bees and flies, which means that plants in species-dense areas are not getting enough pollen to reproduce. The study’s team leaders, Jana Vamosi, Susan Mazer and Tiffany Knight, believe that if the current state of affairs continues in species-rich hotspots, plant extinctions are unavoidable. The researchers proffer a number of possible reasons for the current parlous state of biodiverse hotspots, but as yet they are still unsure as to whether this is a recent phenomenon or whether they are simply witnessing something that has been occurring for millions of years; a situation that reflects the lack of existing knowledge in this area. Vamosi, Mazer, Knight performed an exhaustive global analysis of more than 1,000 pollination studies that included 166 different plant species. Their study, appearing in the Proceedings of the National Academy of Sciences, found that plants suffer lower pollination and reproductive success in areas where there is considerable plant diversity. The analysis shows that ecosystems with the greatest number of species - including the jungles of South America and Southeast Asia and the rich shrub land of South Africa - have bigger deficits in pollination compared to the less-diverse ecosystems of North America, Europe and Australia. "This is truly a synthetic work," said Susan Mazer, a professor of biology at the University of California, Santa Barbara. "Our detection of global patterns required the simultaneous analysis of many studies conducted independently by plant ecologists all over the world." Mazer said their meta-study analyzed 482 field experiments on 241 flowering plant species conducted since 1981. The work took several years to complete and all continents except Antarctica are represented. "This analysis can tell us things about ecological processes at the global scale that individual studies are not designed to tell us," she said, noting that the synthesis could not have been done 25 years ago because few careful field studies of this type had yet been conducted. A typical field study compared plants that were naturally pollinated to those to which pollen was added by hand. If the plants that received human intervention showed increased fruit, then it was clear that the naturally pollinated flowers were not getting enough pollen to achieve maximum fruit production. "If pollinators are doing a good job, you wouldn't expect a treatment effect," Knight said. "But for some of our plants we saw a huge treatment effect. We saw that a lot of the plants are incredibly pollen-limited.” For some plant species, this reduction in fruit and seed production caused through lack of pollination could drive them towards extinction. The team found this pattern to be especially true for species that rely heavily on pollinators to assist with outcrossing (seeding a flower’s stamen with pollen sourced from another flower of the same species) for reproduction, because individuals of the same species tend to be separated by large distances when species diversity is high. This separation means that pollinators have to fly long distances to deliver pollen, and when they do arrive, they may deliver lots of unusable pollen from other plant species. Not being able to outcross means that extinctions are a real likelihood. While it is possible for plants to self-pollinate (selfing), this alone does not progress or strengthen the species, as, like any other living organism, a plant needs genetic variation in order for the species to survive as a whole. In short, selfing does not deliver the genetic variation that may increase the fitness of a plant’s progeny. The new study does not bode well for life globally, as many of the so-called biodiverse hotspots are home to many valuable organic compounds, used for medicines and other applications. "Biodiversity hotspots, such as tropical rainforests, are a global resource – they are home to many of the known plants used for medicine and may be a source for future cures, and they absorb huge amounts of carbon dioxide and generate volumes of clean oxygen. Our research suggests that plants in these areas are also very fragile. They already suffer from low pollen receipt, and future perturbations of the habitat may exacerbate the situation," said Knight. That’s a scenario that would not auger well for human progress, but Knight’s comment also implies another explanation for this drastic state of affairs. It seems that we humans like to shoot ourselves in the foot every so often, as many of the biodiverse hotspots also happen to be areas where habitat is being destroyed either directly or indirectly through human intervention. "Pollinators are on the decline globally because of habitat loss and destruction, pesticide use, invasive species, and extinction of vertebrates," said co-researcher Tia-Lynn Ashman. "The concern is that we are losing habitat really rapidly globally, especially in tropical areas, and losing pollinators there as well," added Knight. 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