A comparison of temporal patterns in the ocean spatial distribution of California's Central Valley Chinook salmon runs

2013 ◽  
Vol 70 (4) ◽  
pp. 574-584 ◽  
Author(s):  
William H. Satterthwaite ◽  
Michael S. Mohr ◽  
Michael R. O'Farrell ◽  
Brian K. Wells

We developed a broadly applicable method for estimating stock-specific spatial distributions based on patterns in contacts per unit effort determined from data collected in ocean fisheries. The method fully accounts for fishing effort and quantifies uncertainty in total contacts due to sampling error and the effects of annual variability in size-at-age on estimated contacts with sublegal-sized fish. As a case study, we used coded-wire tag recoveries to compare ocean spatial distributions among fish from four return run timings (fall, late-fall, winter, and spring) of Chinook salmon from the Central Valley, California, USA, and explored how distributions varied annually, seasonally, and with fish age in the data-rich fall run. All runs were rarely contacted in ocean fisheries north of Cape Falcon, Oregon (45°46′N). Late-fall and winter run fish appeared relatively restricted to the south compared with fall run fish, corresponding to life history differences and highlighting the ability of spatial management to control impacts on the endangered winter run. For the fall run, the location of highest relative contacts per unit effort of age-3 fish varied across years. This variation correlated with sea surface temperature the previous summer, suggesting ocean distributions may be more responsive to the environment than previously appreciated.

Author(s):  
Patricia Brandes ◽  
◽  
Brian Pyper ◽  
Michael Banks ◽  
David Jacobsen ◽  
...  

There are four distinct runs of Chinook Salmon (Oncorhynchus tshawytscha) in the Central Valley, named after their primary adult return times: fall, late-fall, winter, and spring run. Estimating the run-specific composition of juveniles entering and leaving the Sacramento–San Joaquin Delta is crucial for assessing population status and processes that affect juvenile survival through the Delta. Historically, the run of juvenile Chinook Salmon captured in the field has been determined using a length-at-date criteria (LDC); however, LDC run assignments may be inaccurate if there is high overlap in the run-specific timing and size of juveniles entering and leaving the Delta. In this study, we use genetic run assignments to assess the accuracy of LDC at two trawl locations in the Sacramento River (Delta entry) and at Chipps Island (Delta exit). Fin tissues were collected from approximately 7,500 juvenile Chinook Salmon captured in trawl samples between 2007 and 2011. Tissues were analyzed using 21 microsatellites to determine genetic run assignments for individuals, which we compared with LDC run assignments. Across years, there was extensive overlap among the distributions of run-specific fork lengths of genetically identified juveniles, indicating that run compositions based on LDC assignments would tend to underestimate fall-run and especially late-fall-run compositions at both trawl locations, and greatly overestimate spring-run compositions (both locations) and winter-run compositions (Chipps Island). We therefore strongly support ongoing efforts to include tissue sampling and genetic run identification of juvenile Chinook Salmon at key monitoring locations in the Sacramento–San Joaquin River system.


2018 ◽  
Vol 59 (1) ◽  
pp. 65-79
Author(s):  
Katarzyna Nikorowicz-Zatorska

Abstract The present paper focuses on spatial management regulations in order to carry out investment in the field of airport facilities. The construction, upgrades, and maintenance of airports falls within the area of responsibility of local authorities. This task poses a great challenge in terms of organisation and finances. On the one hand, an active airport is a municipal landmark and drives local economic, social and cultural development, and on the other, the scale of investment often exceeds the capabilities of local authorities. The immediate environment of the airport determines its final use and prosperity. The objective of the paper is to review legislation that affects airports and the surrounding communities. The process of urban planning in Lodz and surrounding areas will be presented as a background to the problem of land use management in the vicinity of the airport. This paper seeks to address the following questions: if and how airports have affected urban planning in Lodz, does the land use around the airport prevent the development of Lodz Airport, and how has the situation changed over the time? It can be assumed that as a result of lack of experience, land resources and size of investments on one hand and legislative dissonance and peculiar practices on the other, aviation infrastructure in Lodz is designed to meet temporary needs and is characterised by achieving short-term goals. Cyclical problems are solved in an intermittent manner and involve all the municipal resources, so there’s little left to secure long-term investments.


Author(s):  
Eddy Mantjoro

Abstract Goals to be achieved through this research are as follows: (1) the scientific explanation about the initial conditions of fishing effort in the area of ​​research in this area is South Minahasa; (2) To obtain information on the historical development of the fish processing industry in North Sulawesi and Minahasa south in particular; (3) To be informed of the obstacles and challenges faced by the fisheries sector investors, especially fish processing timber. This research focuses on one unit of the fish processing industry wooden fish processing plant, and then in the case study method is relevant. The case study method is expected that researchers can examine more detailed and focused on problems experienced by fish processing company. As a consequence the results can not be generalized as like which would otherwise require science. Unless some case studies on the same topic on other companies and the result is the same, the efforts generalizations can be made. However the results of the case study can paint a picture on the history, constraints and barriers to investment that occur in similar industries and other industries. The initial condition of fisheries business investment in South Minahasa in 1995 was still dominated by small-scale businesses, which is limited to household livelihoods of fishermen. How governance is still very traditional in terms of business objectives just to meet daily food needs. Wooden fish processing technology already existed and developed since the year 700 BC in Japan. In Indonesia, especially in North Sulawesi started introduced in 1927 by a Japanese man named Hara Ko. The new investment started in 1971 until now. Investment in fish processing faces many obstacles and challenges, namely (1) the limited market share, (2) Legal certainty is not guaranteed, (3) Investors from outside the region and abroad to invest by holding on minimal information about the culture and traditions of local communities (4 ) morale of local residents very traditional if not arguably worse. (5) The investment policy is supported by the local government level only at the Regent while Assiten level, down to the village more displays of terror and intimidation to investors. Keywords: fish factory, investment, history, constraints, obstacles Abstrak Tujuan yang ingin dicapai melalui penelitian ini ialah sebagai berikut: (1) Penjelasan ilmiah tentang kondisi awal usaha perikanan di wilayah penelitian dalam hal ini Daerah Minahasa Selatan. (2) Memperoleh informasi tentang sejarah perkembangan industri pengolahan ikan di Sulawesi Utara dan Minahasa selatan khususnya. (3) Mendapatkan informasi mengenai kendala dan tantangan yang dihadapi oleh investor bidang perikanan khususnya pengolahan ikan kayu. Penelitian ini berfokus pada satu unit industri pengolahan ikan yakni pabrik pengolahan ikan kayu, maka metode studi kasus di pandang relevan. Metode studi kasus diharapkan peneliti dapat mengkaji lebih rinci dan fokus pada masalah yang dialami oleh perusahan pengolahan ikan. Sebagai konsekwensinya hasil penelitian tidak dapat digeneralisir sebagai layaknya yang di syaratkan oleh ilmu pengetahuan. Kecuali beberapa studi kasus dengan topik yang sama pada perusahan lain dan hasilnya sama maka upaya generalisasi dapat dilakukan. Walau demikian hasil studi kasus dapat melukiskan gambaran mengenai sejarah, kendala dan hambatan investasi yang terjadi pada industri sejenis dan industri lainnya. Kondisi awal usaha perikanan di wilayah Minahasa selatan pada tahun 1995 ketika investasi pabrik pengolahan ikan kayu di mulai masih didominasi oleh usaha skala kecil, yaitu sebatas mata pencaharian rumah tangga nelayan. Cara kelola pun masih sangat tradisional dalam pengertian tujuan usaha hanya untuk memenuhi kebutuhan makanan harian. Teknologi pengolahan ikan kayu sudah ada dan berkembang sejak tahun 700 sebelum masehi di Jepang. Di Indonesia khususnya di Sulawesi Utara mulai di perkenalkan pada tahun 1927 oleh orang Jepang bernama Hara Ko. Investasi baru dimulai pada tahun 1971 hingga sekarang. Investasi bidang pengolahan ikan menghadapi banyak kendala dan tantangan, yaitu (1) keterbatasan pangsa pasar, (2) Kepastian hukum tidak terjamin, (3) Investor dari luar daerah dan luar negeri berinvestasi dengan berpegang pada informasi minim mengenai budaya dan tradisi masyarakat lokal (4) moral kerja penduduk lokal amat tradisional jika tidak boleh dikatakan buruk.(5) Kebijakan investasi ditunjang oleh pemerintah daerah hanya pada level Bupati sedangkan level assiten, ke bawah sampai kelurahan lebih banyak menampilkan teror dan intimidasi kepada investor. Kata Kunci : pabrik ikan, investasi, sejarah, kendala, hambatan


2017 ◽  
Vol 5 (1) ◽  
pp. 39
Author(s):  
Jean Marc Ecoutin ◽  
Dharmadi Dharmadi
Keyword(s):  

Fishing effort is often a difficult parameter to identify in halieutic st,udies and even more so if the study involves coastal and artisanal frshing spread along a coast more than 1,000 km long.


Resources ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 40 ◽  
Author(s):  
Emmanouil Tyllianakis ◽  
Lenka Fronkova ◽  
Paulette Posen ◽  
Tiziana Luisetti ◽  
Stephen Mangi Chai

This study presents an ecosystem-services-mapping tool that calculates the monetary value of several ecosystem services (ES) provided from an area comprising both MPAs (Marine Protected Areas) and non-managed areas. Findings in the UK South West Marine Management Organisation (MMO) Plan Area show that different MPAs yield high value estimates and that activities are grouped in certain areas, with the Severn Estuary and surrounding Site(s) of Special Scientific Interest (SSSI) attracting the most recreational anglers, despite having lower water quality. This can be explained by increased nutrient levels, which enhance biological activity and yet do not cause oxygen depletion. The yearly value of the ecosystem service of carbon sequestration and storage in the area is estimated between £16 and £62 thousand. Proximity to large urban areas and shallow waters appear to be the most appealing factors for anglers, while proximity with France can be associated with the high fishing effort in the southwest of the study area. We show that the use of a tool integrating a willingness-to-pay function with high spatial resolution layers and associated monetary values can be used for short-term marine spatial planning and management.


2019 ◽  
Vol 76 (6) ◽  
pp. 1554-1566
Author(s):  
Fabien Pointin ◽  
Fabienne Daurès ◽  
Marie-Joëlle Rochet

Abstract The EU Landing Obligation (LO) is designed to reduce bycatch (i.e. unwanted catch) through more selective fishing practices, such as avoidance behaviours which consist in allocating fishing effort to other species, fishing grounds or seasons. Incentives for fishers to change their behaviours depend on their economic performances as well as their ability to avoid bycatch. Changes in economic performances under the LO are evaluated based on cost and revenue equations. The nested grid method is then used to explore the spatial and temporal distribution of landings and discards, and to suggest alternative effort allocation to avoid bycatch. This article is focussed specifically on the French otter trawl fishery in the eastern English Channel and southern North Sea. Results suggest that under the LO the choke species problem will curtail fishing activities earlier in the year, leading to significant economic losses. In the absence of significant quota top-ups (at least 75%), a change in fishing practices consisting in reducing overall bycatch by 30% is insufficient to reduce losses. With a particular attention to choke species, more economically efficient avoidance strategies can be found thanks to the nested grid method.


1999 ◽  
Vol 22 (6) ◽  
pp. 705-720 ◽  
Author(s):  
Nicholas Bax ◽  
Rudy Kloser ◽  
Alan Williams ◽  
Karen Gowlett-Holmes ◽  
Tim Ryan

1995 ◽  
Vol 71 (5) ◽  
pp. 627-632 ◽  
Author(s):  
János Gál ◽  
Imre E. Bella

In this case study of the Saskatchewan provincial timber inventory, the major sources of errors were identified and suitable procedures presented for their estimation. Applying those procedures on a pilot area, the results showed that sampling error was by far the most important component affecting the accuracy of volume estimates. Variances arising from the use of taper functions to estimate tree volumes were under 0.05%, and variances from 3P subsampling were about 3% of the total variance. A computer simulation experiment showed that a 2% measurement bias in both diameter and height measurements may result in 8% bias in the volume estimate. Key words: 3P sampling, taper functions, error budget


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