Update on scallop meat quality from RSA research CFF: Liese Siemann, Luisa Garcia, Samir Patel, and Ron Smolowitz UM: Carl Huntsberger RWU: Roxanna Smolowitz and Ava Mastrostefano NOAA: Heather Haas MAAS: Bob Prescott and Karen Dourdeville
Gray meat modeling • Goal is to examine the impact of biotic and abiotic factors on gray meat prevalence and the likelihood of individual scallops having gray meats • Five survey trips between August 2013 and March 2014 on the southern portion of Georges Bank and fifteen survey trips between August 2015 and June 2017 on the northern portion of Georges Bank • Meat quality was assessed based on a qualitative color scale with three categories with colors ranging from white to brown to gray • A subset of the collected meats were evaluated for the presence of apicomplexan parasites at the Aquatic Diagnostic Laboratory at Roger Williams University
Total numbers of scallops assessed during each survey month. Survey month and year Number of scallops sampled September 2013 396 October 2013 380 December 2013 364 January 2014 363 March 2014 399 August 2015 411 September 2015 558 October 2015 557 November 2015 605 January 2016 563 March 2016 654 May 2016 641 June 2016 527 July 2016 530 October 2016 517 November 2016 385 January 2017 483 March 2017 520 May 2017 628 June 2017 502 9,983 scallops sampled 4.92% had gray or brown meats
Scallop relative abundance
• Gray meat prevalence at each station for each survey trip was modeled using a quasibinomial distribution • Meat quality of individual scallops , as gray meat presence (gray or brown) or absence (white), was modeled using a binomial distribution • Southern and northern stations were modeled separately due to the survey area shift between 2014 and 2015 • Fixed effects used for modeling • location (“easting” and “northing” in UTM space) • bottom depth (29 – 106 m) • bottom temperature (4 - 19 ° C) • scallop density (0.38 - 640 bushels/km 2 ) • clapper ratio as proxy for natural mortality (0 - 2.0) • scallop reproductive stage • shell height • area (Closed Area I, Closed Area II, open) • downstream distance from a closed area (in a closed area, < 5 km from a closed area, between 5 and 10 km from a closed area, or >10 km from a closed area)
Selected models Southern Georges Bank 2013-2014 Significant effects included Significant effects included • • location location • • average shell height shell height • • clapper ratio clapper ratio • • area (high in Closed Area I ) area (high in Closed Area I ) • scallop density Northern Georges Bank 2015-2017 Significant effects included Significant effects included • • location scallop density • • bottom depth shell height • • percentage of spent scallops reproductive stage Gray meat prevalence Meat color/quality
Southern vs northern Georges Bank Southern Georges Bank Northern Georges Bank 2013-2014 2015-2017 Gray meats were more common when Gray meats were more common when • • scallops were large (older) scallops were spent • in areas with high natural mortality • in a localized area (Closed Area I) Suggests different causes for gray meats observed in these areas (and years) – disease vs stress/energy depletion following spawning?
Apicomplexan parasite in discolored meats from northern Georges Bank Relationship between meat color and severity of infection (assessed using histological techniques) and presence of parasite (assessed using PCR) is unclear Protozoan Meat color PCR +/- number White 0 Negative Tan 0 Positive * Tan 6 Negative * Tan 9 Negative * Brown 22 Positive Brown 28 Positive Brown 35 Positive Gray 0 Positive * Gray 3 Negative * Gray 13 Positive Gray 13 Positive Gray 15 Positive * Protozoan number vs PCR detection of parasite don’t agree
Most recent data on gray meats on Georges Bank (2017-2018) December had more gray meats, and October and April more brown meats Scallop Brown Gray Orange Year Month sampled meat meat nodules August 873 5 2 1 September 782 3 1 0 2017 October 777 13 2 2 December 754 7 4 1 January 755 8 1 0 February 841 4 1 2 2018 April 745 15 1 0 June 864 4 0 0
Orange pustules (2013-2017) Orange Year Month Scallops sampled Orange nodules - mycobacterium Pustules September 396 8 2013 October 380 5 December 364 4 January 363 4 2014 March 399 5 August 411 4 September 558 0 2015 October 557 4 November 605 5 January 563 3 March 654 5 May 641 3 2016 June 527 1 July 530 0 October 517 0 November 385 0 January 483 0 March 520 0 2017 May 628 0 June 502 1 Grimm C, Huntsberger C, Markey K, Inglis S, and Smolowitz R. 2016. Found in scallops from Identification of a Mycobacterium sp. as the causative agent of orange nodular lesions in the Atlantic sea scallop stations where gray meats Plactopecten magellanicus . Diseases of Aquatic Organisms 118: 247 – 258 were also prevalent
Nematodes and Turtles Since 2016, CFF has been taking Total Turtles Positive Nematode Year Tagged Dead Tagged Dead lavage samples from live turtles, and 2016 22 28 6 1 gut content/fecal samples from dead 2017 22 10 5 1 turtles that strand on Cape Cod. 16% 2018 35 33 7 4 of all turtles have been positive for Total 79 71 18 6 nematodes. CCL mean ± SD (cm) 79.9 ± 9.6 81.4 ± 9.3 Turtles +Nematode 2016 2017 2018 S. sulcata egg Microplastic?
Nematodes and Turtles
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