Habitat and Biology
Climatic zone: Polar.
Water Area Overview
The Northwest Pacific (Area 61, Figure B10.1) has a number of large, productive areas of continental shelf including the northern portion of the South China Sea, the East China Sea, the Yellow Sea, the Sea of Japan and the Sea of Okhotsk. Other subareas have less extensive areas of continental shelf with productive fisheries. These subareas include the western portion of the Bering Sea and the ocean east of the Japanese archipelago, the Kuril Islands, and the southeast part of the Kamchatka Peninsula. The enhanced productivity in these regions comes from the interaction and confluence of the Kuroshio and Oyashio western boundary currents. These interactions produce zones of enrichment and concentration of biological processes. The total surface area of the Northwest Pacific (Area 61) is close to 19 million km2, including the third-largest shelf area at about 3.6 million km2.
|Figure B10.1 The Northwest Pacific (Area 61) |
Considered a single stock: No
PROFILE OF CATCHES
Nominal catches in the Northwest Pacific increased to 24 million tonnes in 1996 and 1997 after a general decline from 1988 to 1994. Catches have since stabilized at about 20 million tonnes, making the Northwest Pacific the most productive FAO Fishing Area. Despite this high productivity, there continues to be concern over increasing fishing effort, IUU fishing, overfished stocks, and degradation of some ecosystems.
Total catches in Area 61 grew steadily from about 4 million tonnes in 1950 to an intermediate peak of 23.6 million tonnes in 1988 (Figure B10.2). Catches declined to 20.4 million tonnes in 1994 because of abrupt declines in the two most important fish
species in the catch, the Japanese pilchard (or sardine) (Sardinops melanostictus) in ISSCAAP Group 35 and the Alaska pollock (Theragra chalcogramma) in Group 32.
The declines in the catches of these two extremely abundant species have been offset by increases in production of other major species. In 1996–1997, catches by industrial fisheries reached almost at the same level as the earlier 1988 peak. Since then, they have declined and stabilized at about 20 million tonnes (Figure B10.2, Table D12).
|Figure B10.2 Annual nominal catches by ISSCAAP species groups in the Northwest Pacific (Area 61) |
Japan used to be the largest fishery country in this area and landed about 10 million tonnes each year in the 1980s. However, its catch dropped rapidly in the 1990s and has remained at about 4 million tonnes a year in the last decade (Figure B10.3). In contrast, China had a relatively low catch of about 2 million tonnes in the 1960s and 1970s but this increased markedly between the mid-1980s and 1990s. After reaching a peak of more than 13.4 million tonnes in 1998, the total landings of China dropped slightly at the end of 1990s and remained at about 12.3 million tonnes in 2009. The Russian Federation/former Soviet Union is ranked third and its landings reached a peak at about 5 million tonnes in the mid-1980s. Its catches have since dropped to the current level of about 2 million tonnes.
The Republic of Korea is also a major fishing country in the Northwest Pacific region, landing about 1.5 million tonnes between 1975 and 2000 and 1.3 million tonnes in 2009.
|Figure B10.3 Annual nominal catches of selected countries in Northwest Pacific (Area 61) |
In the Northwest Pacific, about 18 percent (a percentage of total catch between 1950 and 2009, calculated from Table D12) of catches are not reported by species and are classified as marine fishes not identified (ISSCAAP Group 39). Cods, hakes, haddocks (Group 32) make the largest known contribution with 15 percent of the total. Alaska pollock had the largest catch of 5 million tonnes in the peak period around 1988. However, pollock catches dropped to a low of 1.1 million tonnes in 2002, with only a slight recovery by 2009 (Figure B10.4). The decline in the pollock may be related to excessive fishing pressure, although the evidence suggests at least some environmental factors were also important (McKinnell and Dagg, 2010). Pacific cod (Gadus macrocephalus) is second only to Alaska pollock, but had much lower landings that equal about 10 percent of the pollock catch. Pacific cod followed the declining trend in pollock and other North Pacific demersal catch from the 1980s to the early 2000s. Since that time, the catch has stabilized at about 111 000 tonnes (Figure B10.4). The highest catches of Pacific cod in Area 61 appear to be made in the Russian Navarin region of the Northern Bering Sea.
|Figure B10.4 Annual nominal catches of selected species in ISSCAAP Groups 32 and 34, Northwest Pacific (Area 61) |
Herrings, sardines and anchovies (ISSCAAP Group 35) form the second-largest group in Area 61, contributing about 15 percent of the total catch on average. Of this group, Japanese pilchard used to be the most important species, with a peak catch of 5 million tonnes in 1988 (Figure B10.5). However, the pilchard stock then collapsed and its catch fell to 282 000 tonnes and has remained at this level. It is believed that the collapse of Japanese pilchard in the late 1980s was the result of natural ecosystem variability associated with the 1988 regime shift (Yatsu et al., 2005; Ohshimo, Tanaka and Hiyama, 2009).
Japanese anchovy (Engraulis japonicus) is also an important species. Its catches increased from 0.3 million tonnes in 1988 to 1.9 million tonnes in 1998, before declining to about 1.4 million tonnes in 2008 (Figure B10.5). Pacific herring (Clupea pallasii) shows a multidecadal pattern in catch. The Sakhalin–Hokkaido stock dominated catches in the period from the 1920s to the 1940s. However, the Okhotsk and West Bering Sea stocks have made the largest contribution since the 1950s (Naumenko, 2001). Catches began showing a downward trend from the early 1970s until the late 1980s. The total catch in 1994 was only one-fourth of the average for the 1960s and 1970s. However, catches increased to a high of 431 000 tonnes in 1998 and decreased slightly to 226 000 tonnes in 2009 (Figure B10.5). Miscellaneous pelagic fishes (ISSCAAP Group 37) make up another 13 percent of the total landings in Area 61. Among them, chub mackerel (Scomber japonicus) is the species with the largest catch. Its catch decreased from 1.6 million tonnes in 1996 to 0.81 million tonnes in 2002, and bounced back to 1.4 million tonnes in 2008 (Figure B10.5). Japanese jack mackerel (Trachurus japonicus) also increased from 0.06 million tonnes in 1980 to 0.37 million tonnes in 1994, thereafter fluctuating between 0.23 million and 0.41 million tonnes (Table D12). Pacific saury (Cololabis saira) declined from the 1950s to the 1980s. The catch then increased from 0.18 million tonnes (1998) to 0.62 million tonnes (2008) and, thus, exceeded the historical peak in 1962 Table D12).
|Figure B10.5 Annual nominal catches of selected species in ISSCAAP Groups 35 and 37, Northwest Pacific (Area 61) |
Species reported as miscellaneous coastal fishes (ISSCAAP Group 33) constitute about 7 percent of the catch, and these have been stable since the early 2000s at between 2.1 million and 2.4 million tonnes (Table D12).
Species reported as miscellaneous demersal fishes (ISSCAAP Group 34) have a catch share of about 6 percent. Largehead hairtail (Trichiurus lepturus) is the major species in this group. Its catches increased from 0.53 million tonnes in 1988 to almost 1.2 million tonnes in 1998 and have been stable since (Figure B10.4).
ISSCAAP Group 57 (squid, cuttlefish, octopuses) produces about 5 percent of the total landings in Area 61. Catches for this group have increased steadily for the last two decades with clear year-to-year fluctuations (Figure B10.6).
Japanese flying squid (Todarodes pacificus), the major species of the group, had large landings in the 1960s, but these declined until the mid-1980s. The catches bounced back to above 600 000 tonnes in 1997, but then dropped to 400 000 tonnes in 2009.
|Figure B10.6 Annual nominal catches of selected species in ISSCAAP Groups 55, 56 and 57, Northwest Pacific (Area 61) |
ISSCAAP Group 36 (tunas, bonitos, billfishes, etc.) constitute about 3 percent of the catch and the catch of this group has been stable since the early 2000s at between 0.63 million and 0.86 million tonnes (Table D12). Catches of ISSCAAP Group 56 (clams, cockles, arkshells) have gradually declined since the 1970s and were about 100 000 tonnes in 2009 and are now only 1.5 percent of the total (Figure B10.6). Yesso scallops of ISSCAAP Group 55 exhibited a steady increase until the mid-2000s and then stabilized at about 0.3 million tonnes.
Salmons, trout, smelts, etc. (ISSCAAP Group 23) contribute only about 2 percent of the total landings. Their catches increased gradually after 1970, with a large jump to 700 000 tonnes in 2009 (Figure B10.7). Yearto-year fluctuations in salmonid catches have always been apparent. Over the whole time period, chum salmon (Oncorhynchus keta) and pink salmon (Oncorhynchus gorbuscha) have always been the major salmon species in the Northwest Pacific. After the 1980s, catches of chum salmon surpassed pink salmon and reached a peak of about 300 000 tonnes in 1996. Since then, chum salmon catches have fluctuated at about 200 000 tonnes (Figure B10.7). The pink salmon catch peaked in 1991, declined abruptly in 1992, and then fluctuated between 100 000 tonnes and 240 000 tonnes for many years before a sudden jump to about 400 000 tonnes in 2009.
|Figure B10.7 Annual nominal catches of selected species in ISSCAAP Group 32, Northwest Pacific (Area 61) |
It is worth noting that the catches of gazami crab (Portunus trituberculatus), shrimps and prawns have been increasing dramatically in the region in the past three decades (Figure B10.8). In contrast, the abundance and frequency of occurrence of gazami crab estimated by trawl surveys in Bohai Sea declined from 1959 to the 1990s (Jin, 2004). Recent catches of gazami crab in the western Japanese waters have also been low.
Management unit: No
The status of each fishery stock in Area 61 is shown in Table D12
. Fisheries in the Northwest Pacific are of great importance not only because they have the highest production among FAO Statistical Areas, but also because countries in the area such as Japan, China and the Republic of Korea have a tradition of eating fish. Fisheries management has been undertaken at both a country and regional level. However, that does not necessarily mean that fisheries resources are well managed.
- Bilateral agreements
At a regional level, bilateral agreements on resource sharing and management are popular. For example, there are three bilateral agreements in the East China Sea and its adjacent seas. The 1965 agreement between Japan and the Republic of Korea concerning fisheries was revised and entered into force in 1999. This agreement was made in order to reflect the 1982 UNCLOS and resolve pending problems among coastal countries in the region (Kang, 2003). The 1975 agreement between China and Japan was also revised and entered into force in 2000. This agreement was intended to enhance cooperative fisheries management in the East China Sea. The agreement between China and the Republic of Korea for cooperative fisheries management in the Yellow Sea entered into force in 2001 (Kang, 2003; Yu and Mu, 2005). However, these agreements leave fundamental problems to be resolved, including: (i) neglect of the biological characteristics of fish stocks that migrate beyond the jurisdiction of one country; and (ii) enforcement and jurisdiction is conducted only by the flag State for broad areas known as “Provisional Waters”, “Middle Waters” and “Transitional Waters” (Kang, 2003).
- Multilateral Regional Fishery agreements
The North Pacific Anadromous Fish Commission (NPAFC) was established in 1993 to promote conservation of anadromous fishes (six species of Oncorhynchus) in the international waters of the North Pacific Ocean and its adjacent seas. The NPAFC is responsible for fisheries north of 33°N that are beyond the 200-mile EEZs of the coastal States. The Western and Central Pacific Fisheries Commission (WCPFC) was established in 2004 for a number of highly migratory species, such as tunas and billfishes, in the western and central Pacific Ocean. A new arrangement on demersal fisheries operating on the high seas of the Northwest Pacific (Area 61) was established in 2007 and has been revised. Multilateral meetings have also been under way to establish a new convention for management of fisheries stocks in the high seas of the Northwest Pacific that are not covered by the NPAFC and WCPFC. The major approach to fishery management in the region is through input and technical controls. The exploitation level of fish stocks is regulated by input restrictions such as limits to the number of vessels and length of fishing season. The advantage of input controls is the ease and low cost of implementation. However, the disadvantage is that the effect of these regulations on total catch is not clear. In some circumstances, even if the number of fishing vessels or total fishing effort is reduced, the catch will not be reduced accordingly. Technical controls are also widely used in fisheries management by regulating the body size of the target species, mesh size of gear and release of artificially reared fry.
- Domestic fishery management
There have been some major developments in domestic fishery management at the national level since the mid-1990s. In addition to the existing measures such as limited entry systems, Japan, the Republic of Korea and the Russian Federation implemented a TAC system for a number of species between 1997 and 2002 (Jamieson and Zhang, 2005). The Japanese Government developed a resource recovery plan in 2002 (Jamieson, Livingston and Zang, 2010). The Chinese Government introduced a negative growth policy, a fishing vessel buy-back programme, and summer fishing moratorium in its all coastal seas (Yu and Yu, 2008). The Republic of Korea started a buy-back programme in 1994 to reduce fishing capacity. It has recently developed a pragmatic ecosystembased fisheries risk assessment method for fisheries of the Republic of Korea. The approach has been designed to measure the risks associated with fisheries relative to three different management objectives, such as sustainability, diversity, and habitat quality (Zhang et al., 2009). China’s summer season fishing moratorium has been implemented in all its coastal seas since 1995. At present, fishing is banned from 16 June to 1 September in the Bohai Sea, from 16 June to 1 September in the Yellow Sea, from 16 June to 16 September in the East China Sea, and from 1 June to 1 August in the South China Sea (FAO, 2009). The ban on major fishing gear in the summer has proved to be cost-effective to implement and monitor. It has resulted in clear benefits for the conservation of fish resources and biodiversity (Jiang et al., 2008).
It is currently recognized that many fisheries are being affected by fishing and climatic and human-induced ecosystem changes such as global warming (Kim, 2010). To cope with the changes in productivity of regional ecosystems, control over fleet capacity and development of operational management procedures may be critical to the long-term sustainability of fisheries in the region (Barange et al., 2009). Establishment of a new convention on the management of international fisheries in northeast Asia has been recommended (Kim, 2010). This will add to the existing arrangements on high seas fisheries of the North Pacific Ocean (see above). Implementation of an ecosystem approach to fisheries or ecosystem-based management has recently started in this region, focusing on: (i) minimizing fishing and other human-induced impacts; (ii) rebuilding depleted fisheries stocks; and (iii) adapting to climate changes and natural disasters. In particular, widespread impacts in the marine environment of land runoff from both industrial and urban developments will be addressed (Jamieson and Zhang, 2005).
Biological State and Trend
To access all FIRMS State and Trend summaries available for this Area, please look at: Status and Trend Summaries (extracted from reports)
Of the fish stocks that have been examined under this increased focus on fisheries management in the Northwest Pacific, only a few fish stocks have been assessed as overfished (Table D12). The most important is largehead hairtail, which mainly occurs in the East China Sea and is targeted by mainly Chinese fleets. In addition, Pacific saury and Japanese flying squid are considered to be non-fully exploited. Most fish stocks are believed to be fully exploited in the area (Table D12). However, it must be noted that the current assessments in Table D12 generally rely on catch criteria, because limited abundance or spawning biomass indices are available. Despite the recent developments in management measures, excessive fishing capacity is still one of the major issues in the Northwest Pacific (Jamieson and Zhang, 2005). For example, the total fishing power of Chinese vessels in the East China Sea increased by 7.6-fold between the 1960s and 1990s. At the same time, their CPU declined by a factor of three (Maguire, 2005). Although the number of Chinese fishing vessels has stabilized since the late 1990s, the total power of vessel engines is still increasing (Yu and Yu, 2008). In coastal seas such as the East China, Yellow and Bohai Seas, there has been a shift in catches from large, high-valued fish to lower-valued smaller species (Tang and Jin, 1999; Zhang, Kim and Huh, 1988; Zhang and Kim, 1999; Jin, 2004, 2008). Reduction in fishing effort is still urgently needed in some areas (e.g. Chen and Shen, 1999; Zhang, Kim and Yun, 1992).
Pilchard, off Japan
The largest variations in catches of marine resources in the Northwest Pacific have been caused by fluctuations in pilchard (or sardine) stocks. The pilchard fishery off Japan grew rapidly in the 1930s to become one of the largest single-species fisheries in the world. Then, in the early 1940s, the stocks abruptly collapsed. It remained depleted for nearly three decades and then suddenly exploded into a rapid rebuilding phase in the early 1970s (Kawasaki, 1983; Yatsu et al., 2005; Ohshimo, Tanaka and Hiyama, 2009). This led, in the 1980s, to catches of more than twice the peak before the earlier collapse. The pilchard stocks, after sustaining a major fishery for a similar period to that of the 1930s and 1940s, declined for a second time. The total catch of the fishery has remained at an extremely low level since the mid-1990s (Figure B10.5). The fluctuations in Japanese pilchard stocks are probably not related to fishing only, but more to climatic and ecosystem changes (Yatsu and Kaeriyama, 2005; Yatsu et al., 2005; Ohshimo, Tanaka and Hiyama, 2009). Given the influence of environmental conditions, it is difficult to classify the stock status of Japanese pilchard. However, the Pacific stock is considered overfished because the fishery is still taking catches above the level that the stock can sustain (Fisheries Agency and Fisheries Research Agency of Japan, 2010). As there have been no fisheries directly targeting the Tsushima Current stock since the 2000s, its stock status is uncertain.
Japanese anchovy, Japanese jack mackerel and Japanese flying squid, off Japan, Yellow Sea and East China Sea
During the rapid decline in pilchard catches in the late 1980s and early 1990s, a strong rebound of catches of Japanese anchovy, Japanese jack mackerel and Japanese flying squid occurred (Figures B10.3 and B10.5, Table 12). There seems to be a strong pattern of high alternating catches of sardine and anchovy stocks in many regions throughout the world (Lluch-Belda et al., 1989; Bakun, 1998; Schwartzlose et al., 1999; Barange et al., 2009). In addition, Japanese anchovy has also become the largest catch in both the Yellow Sea and the East China Sea. This seems to have occurred after removal of demersal and pelagic predatory fishes by heavy fishing (Tang and Jin, 1999). However, the anchovy fishery in the Bohai Sea nearly collapsed in 2001 (Jin, 2004). In recent years, the stocks of Japanese flying squid have maintained a moderate to high biomasses and are not considered to be fully exploited (Fisheries Agency and Fisheries Research Agency of Japan, 2010).
Alaska pollock, western Bering Sea and Sea of Okhotsk
The recent rebound in the Alaska pollock catch is associated with an increase in catches of the Russian Federation from the western Bering Sea (Navarin region) since 2003 and the Sea of Okhotsk since 2007. Pollock biomass doubled in the Sea of Okhotsk in the 2000s compared with the 1990s (McKinnell and Dagg, 2010). Other major pollock stocks are believed to be currently at substantially lower biomasses than in the 1980s (McKinnell and Dagg, 2010). The pollock fishery in the international waters of the “Doughnut Hole” in the Bering Sea produced very high catches in the late 1980s and early 1990s. However, it was suspended in 1993 owing to overfishing and has still not recovered (McKelvey, Honkalehto and Williamson, 2006).
Yellow croaker, Northwest Pacific
Yellow croaker has recovered since the early 1990s. Fishing pressure on this species increased substantially between the 1950s and the 1980s. As a consequence, the size of fish and proportion of older fish in the stock have continually declined (Jin, 2008). Therefore, the recovery is more likely to have been the result of favourable oceanographic conditions than changes in fishing practices. The increase in chum salmon catch in the past three decades is considered to be due to improved marine survival and/or hatchery rearing and releasing practices (Yatsu and Kaeriyama, 2005; McKinnell and Dagg, 2010). Although the catch of largehead hairtail has increased since the late 1980s, mean body size declined continuously from the 1960s to the 1990s. Overfishing is still a problem in the East China Sea despite the introduction of a “summer fishing moratorium” in 1995 (Xu, Liu and Zhou, 2003).
Multispecies fishery, South China Sea
The northern South China Sea supports a tropical multispecies fishery. The majority of high-trophic level demersal stocks appear to be depleted and most low-trophic fishes are considered overfished (Qiu, Lin and Wang, 2010). The fishery remained open access until the late 1990s. This led to a continuous increase in fishing effort, which was especially rapid from the 1970s to 1990s. As a result of the increasing fishing effort and expansion of fishing into offshore waters, catch trends of the fishery became domeshaped, with a long-term decline. This pattern in catch was seen first in the inshore fisheries and then in the offshore demersal catches. Total catch and catches of the low-trophic species rose until the 1990s, but eventually declined under high fishing pressure. Although fishing effort has levelled off since the late 1990s because of strict licensing controls, total stock density has remained at a low level. It is expected that further reductions in fishing effort will be needed in order to recover the stocks and subsequently raise the total catch.
Environmental problems affecting fisheries in the Northwest Pacific include land reclamation, heavy metals and chemical pollution, oil spills, eutrophication, hypoxia, invasion and escape of non-native species, and impacts of extensive mariculture (She, 1999; Jin, 2004; Maguire, 2005; McKinnell and Dagg, 2010). There appears to be an increasing frequency of red tides and outbreaks of harmful algae, macroalgae and giant jellyfish (Nemopilema nomurai) (She, 1999; Jamieson and Zhang, 2005; Liu et al., 2009; McKinnell and Dagg, 2010). In the Yellow Sea, bacterial epidemics are causing mortality of cultured shrimp (Maguire, 2005) and there is a risk that these could spread to adjacent open waters. The Sea of Okhotsk is the site of frequent earthquakes and the oil drilling that is poised to begin there is a cause for concern because of the high risk of oil spills (Maguire, 2005).
Source of information
Marine and Inland Fisheries Service, Fisheries and Aquaculture Resources Use and Conservation Division. FAO Fisheries and Aquaculture Department “Review of the state of world marine fishery resources”
. FAO FISHERIES AND AQUACULTURE TECHNICAL PAPER.
No. 569. Rome, FAO. 2011. http://www.fao.org/docrep/015/i2389e/i2389e.pdf
The bibliographic references are available through the hyperlink displayed in "Source of Information".ACKNOWLEDGEMENTS
The authors would like to thank Chang Ik Zhang from the Institute of Fisheries Science, Pukyong National University, Korea and Yongsong Qiu from the South China Sea Fisheries Research Institute, China for their valuable comments and inputs.