60 research outputs found

    Early Marine Migration Patterns of Wild Coastal Cutthroat Trout (Oncorhynchus clarki clarki), Steelhead Trout (Oncorhynchus mykiss), and Their Hybrids

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    Hybridization between coastal cutthroat trout (Oncorhynchus clarki clarki) and steelhead or rainbow trout (Oncorhynchus mykiss) has been documented in several streams along the North American west coast. The two species occupy similar freshwater habitats but the anadromous forms differ greatly in the duration of marine residence and migration patterns at sea. Intermediate morphological, physiological, and performance traits have been reported for hybrids but little information has been published comparing the behavior of hybrids to the pure species.This study used acoustic telemetry to record the movements of 52 cutthroat, 42 steelhead x cutthroat hybrids, and 89 steelhead smolts, all wild, that migrated from Big Beef Creek into Hood Canal (Puget Sound, Washington). Various spatial and temporal metrics were used to compare the behavior of the pure species to their hybrids. Median hybrid residence time, estuary time, and tortuosity values were intermediate compared to the pure species. The median total track distance was greater for hybrids than for either cutthroat or steelhead. At the end of each track, most steelhead (80%) were located near or north of the Hood Canal, as expected for this seaward migrating species, whereas most cutthroat (89%) were within 8 kilometers of the estuary. Most hybrids (70%) were detected leaving Hood Canal, though a substantial percentage (20%) remained near the Big Beef Creek estuary. More hybrids (7.5%) than pure cutthroat (4.5%) or steelhead (0.0%) were last detected in the southern reaches of Hood Canal.Given the similarity in freshwater ecology between the species, differences in marine ecology may play an important role in maintaining species integrity in areas of sympatry

    Photography-based taxonomy is inadequate, unnecessary, and potentially harmful for biological sciences

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    The question whether taxonomic descriptions naming new animal species without type specimen(s) deposited in collections should be accepted for publication by scientific journals and allowed by the Code has already been discussed in Zootaxa (Dubois & NemĂ©sio 2007; Donegan 2008, 2009; NemĂ©sio 2009a–b; Dubois 2009; Gentile & Snell 2009; Minelli 2009; Cianferoni & Bartolozzi 2016; Amorim et al. 2016). This question was again raised in a letter supported by 35 signatories published in the journal Nature (Pape et al. 2016) on 15 September 2016. On 25 September 2016, the following rebuttal (strictly limited to 300 words as per the editorial rules of Nature) was submitted to Nature, which on 18 October 2016 refused to publish it. As we think this problem is a very important one for zoological taxonomy, this text is published here exactly as submitted to Nature, followed by the list of the 493 taxonomists and collection-based researchers who signed it in the short time span from 20 September to 6 October 2016

    The GITEWS ocean bottom sensor packages

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    The German-Indonesian Tsunami Early Warning System (GITEWS) aims at reducing the risks posed by events such as the 26 December 2004 Indian Ocean tsunami. To minimize the lead time for tsunami alerts, to avoid false alarms, and to accurately predict tsunami wave heights, real-time observations of ocean bottom pressure from the deep ocean are required. As part of the GITEWS infrastructure, the parallel development of two ocean bottom sensor packages, PACT (Pressure based Acoustically Coupled Tsunameter) and OBU (Ocean Bottom Unit), was initiated. The sensor package requirements included bidirectional acoustic links between the bottom sensor packages and the hosting surface buoys, which are moored nearby. Furthermore, compatibility between these sensor systems and the overall GITEWS data-flow structure and command hierarchy was mandatory. While PACT aims at providing highly reliable, long term bottom pressure data only, OBU is based on ocean bottom seismometers to concurrently record sea-floor motion, necessitating highest data rates. This paper presents the technical design of PACT, OBU and the HydroAcoustic Modem (HAM.node) which is used by both systems, along with first results from instrument deployments off Indonesia
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