Seasonal Mortality of Wild Atlantic Menhaden (Brevoortia tyrannus) Is Caused by a Virulent Clone of Vibrio (Listonella) anguillarum; Implications for Biosecurity along the Atlantic Coastal United States
Table 3
Summary of gross, bacteriological, and histopathologic findings from three different B. tyrannus mortality events off the coast of New Jersey.
Finding
Fall 2020
Spring 2021 (E)
Spring 2021 (M)
Spring 2021 (L)
Fall 2021
Gross necropsy
Eye hemorrhage
6/30
0/12
10/32
4/12
1/5
Skin/fin hemorrhage
18/30 L
4/12 L 3/12 S
16/32 L
3/12 L
0/5
Anchor worm
18/30
9/12
7/32
9/12
5/5
Brain congestion and hemorrhage
21/30
0/30
15/32
0/12
3/5
Splenomegaly
0/30
7/12
0/32
0/12
0/5
Multifocal liver hemorrhage
0/30
7/12
0/32
0/12
0/5
Bacterial isolation
V. anguillarum
2/2
10/12
26/32
8/12
5/5
Yersinia ruckeri
0/2
0/12
2/12
3/12
0/5
Histology findings
Brain hemorrhage
23/30
2/12
10/12
2/6
0/3
Encephalitis and necrosis
13/30
0/12
0/12
2/6
1/3
Meningitis
13/30
0/12
10/12
2/6
1/3
Bacterial rods in brain
2/30
0/12
2/12
2/6
0/3
Renal hematopoietic necrosis
28/30
7/12
1/12
2/6
0/3
Splenic congestion
9/30
7/12
3/12
0/6
2/3
Splenic hematopoietic necrosis
11/30
0/12
0/12
1/6
0/3
Hepatic perivasculitis
16/30
2/12
4/12
3/6 L
0/3
Multifocal hepatic hemorrhage
0/30
2/12
0/12
0/12
0/3
In an ongoing mortality from the spring of 2021, three temporal samples were taken in the early (E), middle (M), and late (L) parts of the mortality event. For skin/fin hemorrhage, lesions were noted to be light (L) or severe (S).
