/pdf/salmon-at-river-s-end-the-role-of-the-estuary-in-the-decline-5cey10pcu8.pdf

Salmon at River's End: The Role of the Estuary in the Decline and Recovery of Columbia River salmon

Different studies have shown that insect meals can partially or completely replace the fish and soya bean meals that are commonly used in aquaculture. However, information is lacking on the amino acid and fatty acid contents and digestibility of different insect meals. Moreover, we evaluated different proportions of insect diets and determined how these affected the nutritional values of insect meals. Our purpose was to clarify these aspects and consider the availability of protein, amino acids, lipids and fatty acids in insect meals in fish nutrition. Generally, insect meals have higher indispensable amino acid contents than other meal types, with contents closely related to those in fish meal. Insect meal can be an important source of essential amino acids such as methionine, with contents ranging between 0.47 and 4.03 g 100 g 1 sample. These values are higher than those reported for other animal and plant meals. In addition, insects are also good sources of lipids and fatty acids, and the amounts and types of fatty acids vary according to the species, stage of development and type of feed. Moreover, the additional nutritional value of insect meal includes compounds such as chitin, which is primarily considered a fibre but also contains nitrogen and amino acids. Insect peptides with activity against pathogenic microflora provide secondary biological effects, which may significantly improve animal health.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/raq.12281

Insect meals in fish nutrition

Research on ghost fishing became active in the late 1980s. Ghost fishing has been confirmed for traps, gillnets, trammel-nets and small seine nets. Some lost traps are functional for a long period of time, even in shallow waters. Consequences for gillnets after loss depend on seabed conditions. The ghost fishing function of gillnets remaining on flat seabeds declines rapidly with decreasing heights and increasing visibility. Gillnets left tangled around an artificial reef, for example, three-dimensionally maintain the initial magnitude of ghost fishing for a long period of time, even after badly fouled. There are increasing numbers of researches working on the total number of mortality per gear after gear loss for gillnets and trammel-nets. It has become also possible to estimate the total number of mortality for a unit period of time in a certain fishing sector. This paper reviews research which has provided evidence and quantitative data on ghost fishing, and proposes five items important for future studies on ghost fishing.

A review of ghost fishing: scientific approaches to evaluation and solutions

West Coast estuaries are geologically young and composed of a variety of geomorphological types. These estuaries range from large fjords to shallow lagoons; from large to low freshwater flows. Natural hazards include E1 Ninos, strong Pacific storms, and active tectonic activity. West Coast estuaries support a wide range of living resources: five salmon species, harvestable shellfish, waterfowl and marine birds, marine mammals, and a variety of algae and plants. Although populations of many of these living resources have declined (salmonids), others have increased (marine mammals). West Coast estuaries are also centers of commerce and increasingly large shipping traffic. The West Coast human population is rising faster than most other areas of the U.S. and Canada, and is distributed heavily in southern California, the San Francisco Bay area, around Puget Sound, and the Fraser River estuary. While water pollution is a problem in many of the urbanized estuaries, most estuaries do not suffer from poor water quality. Primary estuarine problems include habitat alterations, degradation, and loss; diverted freshwater flows; marine sediment contamination; and exotic species introductions. The growing West Coast economy and population are in part related to the quality of life, which is dependent on the use and enjoyment of abundant coastal natural resources.

Geographic signatures of North American West Coast estuaries

The human footprint is now large in all the Earth’s ecosystems, and construction of large dams in major river basins is among the anthropogenic changes that have had the most profound ecological consequences, particularly for migratory fishes. In the Columbia River basin of the western USA, considerable effort has been directed toward evaluating demographic effects of dams, yet little attention has been paid to evolutionary responses of migratory salmon to altered selective regimes. Here we make a first attempt to address this information gap. Transformation of the free-flowing Columbia River into a series of slackwater reservoirs has relaxed selection for adults capable of migrating long distances upstream against strong flows; conditions now favour fish capable of migrating through lakes and finding and navigating fish ladders. Juveniles must now be capable of surviving passage through multiple dams or collection and transportation around the dams. River flow patterns deliver some groups of juvenile salmon to the estuary later than is optimal for ocean survival, but countervailing selective pressures might constrain an evolutionary response toward earlier migration timing. Dams have increased the cost of migration, which reduces energy available for sexual selection and favours a nonmigratory life history. Reservoirs are a benign environment for many non-native species that are competitors with or predators on salmon, and evolutionary responses are likely (but undocumented). More research is needed to tease apart the relative importance of evolutionary vs. plastic responses of salmon to these environmental changes; this research is logistically challenging for species with life histories like Pacific salmon, but results should substantially improve our understanding of key processes. If the Columbia River is ever returned to a quasinatural, free-flowing state, remaining populations might face a Darwinian debt (and temporarily reduced fitness) as they struggle to re-evolve historical adaptations.

/pdf/evolutionary-responses-by-native-species-to-major-fmzhp5973g.pdf

Evolutionary responses by native species to major anthropogenic changes to their ecosystems: Pacific salmon in the Columbia River hydropower system

Utilization of the Columbia River Estuary by Subyearling Chinook Salmon

L; t t l . i i kn ,^ \n dh , ) ! t th , j F r o n 1 . p r i l L h r o r r g h ( ) ( ' t r l h l ' | l 9 B 8 . 1 l l c l i u 1 i n g ( o | o g 1 o l j i r r e n i | e i l h i t e s t R i re r . Orera l l . th t tL rb+drc l l i r rg an l rh i l \ \ l A tuph iun roL t ron is \ !as the most impor ranr p re" fo r the two s ize c lasses o l juvd i l . {h i te i ru rg . , )n s t ,k l i ( !1 . Hr*ocr d r r ing u I s rnp l i rs ry r iods end er bo lh e reas iR i re r K i lomerers [nKm] l5 j l and 2111, S ;e C la$ I {hii{' st,,rg.r,,, (1,1,1-:150 li,rk crsrhl pf(vdl more heurilr on al rdlmonis than did Size Class II white sturg.oo (jlsl Lo 721 n n l ' 0 l h . l t { , d l 1 l , ' ! l | \ i l j l ) 0 | t l n L I ' r ( ] \ l o r S i l i ] c h s s I v h i l | 5 l u r g e o n n r c l l r d e d L i l o p J u n l r r rae . and ernach, r bt\ ^l\ e c orbicul d tlu n i n tha t j r r ren i lesh i tes t r r rgeonnrhot l ia reasco l ta i r led a | r . t | l . l ' | a t i r rn .h i1 rsbet l 'eenr lens i t ies lnbund!Dces)o fspec i fcbenth i .o rgaDis Insandwhi t r : lS j l anr l 2 l l . l ) , s r ) i r . rh , impor ruc . o l Cotuph iun t soLmani t ln rhe r t ie ts o f iu ren i le wh i te s tu r ! :eon. i t $as no t abur r lan t i r Lhr : h r rh , ,s 1n [an , l f rs i t \ . <185 r , rgan ismstnr in {p r i l rnd Seprember ) . Introduction 'Ihc rrhitc sturgeon \Acipensel transn:,n:irn:4j'), tI:,e lalgest North American sturgeon. is an anaclnrmous species frrLrrrrl ahng thc r,".cst coast of North Amclica from the Aleutian l-.Lrnds, -{laska. to Monterev. Cali iornia (Scott and Crossrnan l9i3). Somc poprr lations in the (lolurnbia Rir,er Basin are essenliallv lanrlbcked duc to darr construction (Cochnaucr et o / . l ' 185 . t s " Jn r " l " f t p r p / a / . l q t ) r . Hi-. toricdl1", the populat ion of r!hite sturge{)n in the ColLrrnbia Rivcr (Orcgon and Washingtoni supportcd an intense comrnercial lisherv. rvith catches peaking;r I892 at rnorc than 2.4 mil l ion kg (Craig and Hacker t9. lo). Hou,eler. dLre to orerf ishing. catchcs clccl incd. and in lB99 the total crtch $,:1s less than i313.250 Lg. During the earlv 1900s. arnLrai catr,hes l 'ere less than l04.930 kg (Craig and Hackcr 19401. Since the earl,v 1900,.. lhi te stulgeon populat ions in thc Colrrmbia Rivcr. part icularlv the one dorrnstrearn l iom Bonnevi l le Darn (the lowerrnost , L ' r n r . r , , , , r , r , J . r r i f i , i ' n t l t l u . l p fu r l im lo r ' t . r n t recreational and comrnercial l isheries. PresenLlv. Lhe Lrwer ColLrmbia River (from thc mouth to Bonnel ' i l le Danr) suppolts onc of thc largest popuht ions of lhi te sturgeon. In 1991, the estirnaLed fecreal ional and conmcrciul har-vcsts in the lo$er (lolumbia River were 22.700 and 3.{}00 f ish. respctiivclv (srashington Dcpartment of l'isheries 170 Nolthwest Science. \rol. 67. No. i l . 199iJ i C r l 9 9 l J l , \ r l ' , \ r d l , \ ! e . S ( C n l i l . A " r r i i , ) f . A l r i s h l s r r q r f ( l and Oregon DeparLmenl ol Fish and Wildl i fe 1992). Based on the number of recreational angler tr ips in 1991. Lhe white stur-geon is sccond onlv to salmonicl spccics as the rnost popular rccrcational lish in the lower (lolurnbia River (S'ashington DeparLment ol Fisbcrics and Orcgon Ilcpanmcnt of l ish and Wildl i fe 1992). LiLt le is knorn about thr ecolo;ry ofwhitc sturgcon. rnd the feeding ecologr of juveni les in par-t icuiar has receired only l imited investigation. Thc diets oi small juvcni lc r,".hitc sturgcon ( { 800 mm total length) have been described in Lhe Sacramento-San Joaquin River Basin. Ctl i fcrrnia (Sclrreiber 1962, Radtke 1966). and in the Colunbia River and i ts estuary (Muir ert rzl . l9BB). Hot 'ever. most ofthe r,hite sturgeon col lected bv l lTuir et ulll9tl9) were {rom thc cstudry; onlv a small numbcr {N (5,1) were col lected upstream from the estuarv over a:J-month pefiod. We eramined thc scasonal fccding charlcterist ics ol t to size classes of juveni le white sturgcon (144-350 mm lork lcngth and 351-724 mm lbrk length) in two areas of the lorver Columbia Rivcr in l9BB. Wc asscsscd both the importance of various prey eaten and the feeding intensiLy. Also, we enamined the relationship betrveen thc fecding cha|atterist ics of juveni le $hitc sturgcon ancl ben thic inverlebrate communit ies and the relaLionship bctlr,ccn whitc sturgcon cdtches and benthic iDvertebrate abundance. \ uolrlrAf,. J A:-:.:t

Feeding Ecology of Juvenile White Sturgeon (Acipenser transmontanus) in the Lower Columbia River

: Our studies in the lower 100-km of the Columbia River estuary quantified historical habitat changes and provided new information about contemporary abundance patterns, life histories, and habitat associations of Chinook salmon. The conceptual framework for this research defined salmon performance in the estuary as the product of three factors: habitat opportunity, habitat capacity, and the structure/life histories of source populations. Our 2002-2008 survey results provided empirical data to support this framework by quantifying Chinook salmon performance in terms of temporal abundance, life history and stock-group diversity, foraging success, and growth, as well as by quantifying the relationships between stock groups and one or more of these factors. In Part I, we detail our reconstruction of historical habitat opportunities and changes in the estuary as influenced by the tide, river flows, and temperature. In Part II, we depict contemporary habitat opportunities based on present-day patterns of salmon distribution and abundance and upon various physical factors that influence fish access to shallow-water rearing areas. In Part III, we compare the capacity of different wetland and nearshore habitats in supporting juvenile Chinook salmon as indicated by variations in prey availability, salmon diet, and rates of consumption. Finally, in Part IV, we examine the effects of upriver population structure and life histories on estuary rearing behavior and performance, including the genetic sources of individual Chinook salmon found within particular habitats and stock-specific patterns of residency and growth. These surveys provided new information about the present estuarine habitat associations of juvenile salmon. They also provided data for estimates of historical change in habitat conditions, estimates of historical change in salmon life histories, and analyses of food webs. Below we summarize major conclusions drawn from these evaluations.

/pdf/estuarine-habitat-and-juvenile-salmon-current-and-historical-3v36zwtlpe.pdf

Estuarine Habitat and Juvenile Salmon: Current and Historical Linkages in the Lower Columbia River and Estuary

Extensive efforts are underway to restore and conserve nearshore shallow water habitats in the Columbia River estuary with the intent of increasing the estuary's capacity to provide food, refuge, and other crucial ecosystem functions for juvenile salmon. Juvenile Chinook Salmon Oncorhynchus tshawytscha, including those from the five Evolutionarily Significant Units listed as threatened or endangered under the U.S. Endangered Species Act, are particularly expected to benefit from the habitat improvements. However, information on the temporal and spatial estuarine distributions of juveniles from specific populations or stocks is lacking and impedes restoration planning for at-risk salmon. We conducted a series of surveys to sample juvenile Chinook Salmon occupying shallow-water habitats with sandy beaches in six hydrogeomorphic reaches across the tidal freshwater portion of the estuary and also at one long-term reference site near the estuary mouth. Sites were sampled bimonthly over 26 months during...

Genetic Identification of Chinook Salmon in the Columbia River Estuary: Stock-Specific Distributions of Juveniles in Shallow Tidal Freshwater Habitats

Escape of Dungeness crabs (Cancer magister) from baited commercial crab pots in the Columbia River estuary was examined. During a 28-day period (12 October-10 November 1982), 185 male crabs were captured and tagged. Sixty percent of the crabs escaped, the majority within 2 days. Size, leg loss, and leg regeneration were not significant factors in escapement.

George T. McCabe

Papers

Utilization of the Columbia River Estuary by Subyearling Chinook Salmon

Feeding Ecology of Juvenile White Sturgeon (Acipenser transmontanus) in the Lower Columbia River

Estuarine Habitat and Juvenile Salmon: Current and Historical Linkages in the Lower Columbia River and Estuary

Genetic Identification of Chinook Salmon in the Columbia River Estuary: Stock-Specific Distributions of Juveniles in Shallow Tidal Freshwater Habitats

Escape of Captured Dungeness Crabs from Commercial Crab Pots in the Columbia River Estuary