Update on scallop meat quality from RSA research CFF: Liese Siemann, - - PowerPoint PPT Presentation

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

• 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

Gray meat modeling

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)
• r 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/km2)
• 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

Significant effects included

• location
• average shell height
• clapper ratio
• area (high in Closed Area I)

Southern Georges Bank 2013-2014 Northern Georges Bank 2015-2017

Significant effects included

• location
• bottom depth
• percentage of spent scallops

Significant effects included

• location
• shell height
• clapper ratio
• area (high in Closed Area I)
• scallop density

Gray meat prevalence Meat color/quality

Significant effects included

• scallop density
• shell height
• reproductive stage

Southern vs northern Georges Bank

Gray meats were more common when

• scallops were large (older)
• in areas with high natural mortality
• in a localized area (Closed Area I)

Northern Georges Bank 2015-2017 Southern Georges Bank 2013-2014

Gray meats were more common when

• scallops were spent

Suggests different causes for gray meats observed in these areas (and years) – disease vs stress/energy depletion following spawning?

Relationship between meat color and severity of infection (assessed using histological techniques) and presence of parasite (assessed using PCR) is unclear

Apicomplexan parasite in discolored meats from northern Georges Bank

Meat color Protozoan number PCR +/- White Negative Tan Positive * Tan 6 Negative * Tan 9 Negative * Brown 22 Positive Brown 28 Positive Brown 35 Positive Gray 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)

Year Month Scallop sampled Brown meat Gray meat Orange nodules 2017 August 873 5 2 1 September 782 3 1 October 777 13 2 2 December 754 7 4 1 2018 January 755 8 1 February 841 4 1 2 April 745 15 1 June 864 4

December had more gray meats, and October and April more brown meats

Orange nodules - mycobacterium

Year Month Scallops sampled Orange Pustules 2013 September 396 8 October 380 5 December 364 4 2014 January 363 4 March 399 5 2015 August 411 4 September 558 October 557 4 November 605 5 2016 January 563 3 March 654 5 May 641 3 June 527 1 July 530 October 517 November 385 2017 January 483 March 520 May 628 June 502 1

Orange pustules (2013-2017)

Found in scallops from stations where gray meats were also prevalent

Grimm C, Huntsberger C, Markey K, Inglis S, and Smolowitz R. 2016. Identification of a Mycobacterium sp. as the causative agent of orange nodular lesions in the Atlantic sea scallop Plactopecten magellanicus. Diseases of Aquatic Organisms 118: 247 – 258

2016 2017 2018

Nematodes and Turtles

Since 2016, CFF has been taking lavage samples from live turtles, and gut content/fecal samples from dead turtles that strand on Cape Cod. 16%

• f all turtles have been positive for

nematodes.

Tagged Dead Tagged Dead 2016 22 28 6 1 2017 22 10 5 1 2018 35 33 7 4 Total 79 71 18 6 CCL mean ± SD (cm) 79.9 ± 9.6 81.4 ± 9.3 Total Turtles Positive Nematode Year

Turtles +Nematode

Microplastic?

• S. sulcata egg

Nematodes and Turtles