Density-dependent capture efficiency of a survey dredge and its influence on the stock assessment of eastern oysters (Crassostrea virginica) in Delaware Bay

Morson, Jason M.; Munroe, Daphne M.; Ashton-Alcox, Kathy A.; Powell, Eric N.; Bushek, David; Gius, Jennifer E.

doi:10.1016/j.fishres.2018.04.012

Cited by 17 publications

(17 citation statements)

References 26 publications

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“…However, dredge-estimated oyster densities were often less variable than quadrat-estimated densities in this study, which can be attributed to the fine-scale (< 10 m) spatial homogeneity that is not detected by the larger area sampled by an oyster dredge. The lower efficiency of the dredge at higher shell densities is similar to that observed by Morson et al (2018). But despite the perceived and observed sampling variability, there is still a strong linear correlation between dredge-based and quadrat-based oyster density estimates over a range of sediment types.…”

Section: Discussionsupporting

confidence: 77%

Crassostrea virginica dredge efficiency in Texas estuaries

Pollack¹,

Palmer²,

Linløkken

2020

Exp Results

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Quantifying and comparing stocks of oysters (Crassostrea virginica) within and among estuaries across the Gulf of Mexico is difficult because the sampling equipment used is either inconsistent among studies, or inefficient. In Texas, USA, stock assessments of oyster populations are made using an oyster dredge, which is an inefficient sampling tool. We compared sampling densities estimated by oyster dredges with more accurate estimates taken by diver-quadrat samples to determine a dredge efficiency rate. Our calculated efficiency rate (0.125) was negatively affected by the number of dead oysters, and the number and volume of total oysters in an area, but not affected by sediment grain size, water quality, and other oyster metrics. The dredge efficiency rate calculated in this study can be applied to past and future dredge-collected oyster quantity data to provide more realistic estimates of oyster densities and allow more accurate stock assessments and comparisons among studies and regions.

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Section: Discussionsupporting

confidence: 77%

Crassostrea virginica dredge efficiency in Texas estuaries

Pollack¹,

Palmer²,

Linløkken

2020

Exp Results

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“…Untuk itu konsep pemanfaatan perikanan tidak an-sich dalam pengendalian input perikanan tetapi juga ekosistem (eco-eficiency) yang juga dapat menurunkan efek dari ghost fishing (Willison & Cote, 2009) dan penggunaan alat tambahan secara berlebihan seperti lampu (Susanto et al, 2017). Kebijakan pengendalian alat tangkap melalui indikator produktivitas di pesisir Banten penting untuk menetapkan ukuran populasi, dan jumlah fishing mortality (Morson et al, 2018) dari alat tangkap yang beroperasi.…”

Section: Berdasarkan Keputusan Menteri Kelautan Danunclassified

Kajian Tingkat Efektifitas Perikanan Untuk Pengembangan Secara Berkelanjutan Di Provinsi Banten

Yonvitner¹,

Boer²,

Kurnia³

2020

JURNAL KEBIJAKAN PERIKANAN INDONESIA

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Efektifitas pengelolaan perikanan harus mempertimbangkan pola produksi dan produktivitas usaha penangkapan. Untuk itu penilaian terhadap efektivitas alat perlu dilakukan untuk menjamin keberlanjutan pengelolaan perikanan. Penelitian ini dilakukan di Provinsi Banten pada tahun 2018 dengan menggunakan data tahun 2003-2017. Analisis efektivitas penangkapan dengan mengunakan matrik analisis antara produksi dan produktivitas. Dan juga didukung dengan analisis statistik deskriptif terhadap sebaran hasil tangkapan. Hasil penelitian untuk kategori alat tangkap yang lebih efektif adalah Payang, Pukat Cincin, Jaring Insang, dan Bagan Perahu. Payang memiliki tingkat produksi 280.560 kg per tahun dan produktivitas 31.612 ton per tahun, Pukat Cincin memiliki produksi sebesar 517,341 ton per tahun dan produktivitas 44.986 per tahun, dan Jaring Insang pada tingkat produksi sebesar 1074.311 ton per tahun dan produktivitas 9.231 ton per tahun. Alat tangkap yang termasuk kategori tidak efektif adalah Sero, Jaring Udang, Rawai Hanyut dan Perangkap. Program rekonstruksi alat tangkap penting untuk mengurangi kapasitas penangkapan ikan dan meningkatkan ekonomi. Dalam hal ini, penelitian ini belum melibatkan skala ekonomi nelayan dalam aktivitas operasi sehari-hari.The effectiveness of fisheries management must consider the pattern of production and productivity of fishing businesses. For this reason, an assessment of the effectiveness of the tools needs to be carried out to ensure the sustainability of fisheries management. This research was conducted in Banten Province in 2018 using data from 2003-2017. Fishing effectiveness analysis using a matrix analysis between production and productivity. And also supported by using statistical analysis of the average value and distribution of catches. The results of the research for the more effective categories of fishing gear were Payang, Pure Seine, Gillnet Drift, and Boat Liftnet. Payang has a production rate of 280,560 kg per year and productivity of 31,612 tons per year, Purse seine has a production of 517,341 tons per year and productivity of 44,986 per year, and Gillnet Drift at a production rate of 1074,311 tons per year and productivity of 9,231 tons per year. The fishing gear included in the ineffective category is Sero, Shrimp net, Drifting Rawai and traps. The reconstruction program is important to reduce fishing capacity and improve the economic community. In this case, this study has not involved the economies of scale of fishermen in daily operations.

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“…Observations are limited to Banta et al (2003), in which the radius of the arc was constrained by the experimental protocol, and so offer only modest guidance. The inherent dredge efficiency was set to 5%, 10%, 20%, or 40%, a range of dredge efficiencies obtained by Morson et al (2018) and Banta et al (2003).…”

Section: Parameter Specificationsmentioning

confidence: 99%

“…Days of fishing allowed to land catch consistent with an assumed F msy $ 0.06 y -1 as a function of oyster density, dredge efficiency, and culling capacity. See Table 1 for simulation parameters. 2007, Mann et al 2004, Morson et al 2018 and has proven to be highly variable. Under fishing conditions, dredge efficiency tends to decrease as the dredge fills and be modified by bottom conditions that change as fishing continues (Powell et al 2001, Powell & Ashton-Alcox 2004, 2013, increasing variability.…”

Section: Metrics Controlling Vessel Performancementioning

confidence: 99%