Interannual variability of ichthyoplankton diversity in the Patos Lagoon estuary Southern Brazil

Study Extent

First samples were taken in January 10, 2000 and last samples were taken in December 6, 2016. Samples are collected monthly and preferably during the first week of the month.

Sampling

Sampling of fish eggs and larvae is made with a 50cm diameter conical net, with a mesh of 300 um and equipped with flow meter. The net is manually hauled on the beach area for 2 people during 2 minutes at 7 stations. In the laboratory, samples are concentrated in 300ml jars and fish eggs and larvae are sorted from the remainder zooplankton. Fish eggs and larvae are then identified to the lowest taxonomic level possible and their total abundance recorded by taxa. Temperature and salinity are registered with a YSI Thermosalinometer with precision of 0.01 ºC and of 0.01 salinity units.

Quality Control

Taxonomic determination was done by the same qualified technical expert for the entire period so far. Data is double checked for typing errors and inadequate values.

Method steps

1. Sampling of fish eggs and larvae is made with a 50cm diameter conical net, with a mesh of 300 um and equipped with flow meter. The net is manually hauled on the beach area for 2 people during 2 minutes at 7 stations. In the laboratory, samples are concentrated in 300ml jars and fish eggs and larvae are sorted from the remainder zooplankton. Fish eggs and larvae are then identified to the lowest taxonomic level possible and their total abundance recorded by taxa and standardized at 100m3. All the collected material is preserved in formaldehyde 4%. Temperature and salinity are registered with a YSI Thermosalinometer with precision of 0.01 ºC and of 0.01 salinity units.

Due to the long sample time, there are different taxonomical categories and classifications that need to be reviewed.

1. Animalia
   rank: kingdom
2. Chordata
   rank: phylum
3. Actinopterygii
   rank: class
4. Anguilliformes
   rank: order
5. Atheriniformes
   rank: order
6. Beloniformes
   rank: order
7. Characiformes
   rank: order
8. Clupeiformes
   rank: order
9. Cyprinodontiformes
   rank: order
10. Elopiformes
    rank: order
11. Gobiesociformes
    rank: order
12. Perciformes
    rank: order
13. Pleuronectiformes
    rank: order
14. Siluriformes
    rank: order
15. Syngnathiformes
    rank: order
16. Achiridae
    rank: family
17. Anablepidae
    rank: family
18. Atherinidae
    rank: family
19. Atherinopsidae
    rank: family
20. Blenniidae
    rank: family
21. Carangidae
    rank: family
22. Characidae
    rank: family
23. Clupeidae
    rank: family
24. Engraulidae
    rank: family
25. Gerreidae
    rank: family
26. Gobiesocidae
    rank: family
27. Gobiidae
    rank: family
28. Hemiramphidae
    rank: family
29. Mugilidae
    rank: family
30. Paralichthyidae
    rank: family
31. Pimelodidae
    rank: family
32. Poeciliidae
    rank: family
33. Sciaenidae
    rank: family
34. Stromateidae
    rank: family
35. Syngnathidae
    rank: family
36. Trichiuridae
    rank: family
37. Anchoa
    rank: genus
38. Atherinella
    rank: genus
39. Blennius
    rank: genus
40. Brevoortia
    rank: genus
41. Catathyridium
    rank: genus
42. Cynoscion
    rank: genus
43. Engraulis
    rank: genus
44. Eucinostomus
    rank: genus
45. Gobiesox
    rank: genus
46. Gobionellus
    rank: genus
47. Gobiosoma
    rank: genus
48. Hyporhamphus
    rank: genus
49. Jenynsia
    rank: genus
50. Lycengraulis
    rank: genus
51. Macrodon
    rank: genus
52. Menticirrhus
    rank: genus
53. Micropogonias
    rank: genus
54. Mugil
    rank: genus
55. Odontesthes
    rank: genus
56. Paralichthys
    rank: genus
57. Paralonchurus
    rank: genus
58. Parapimelodus
    rank: genus
59. Parona
    rank: genus
60. Peprilus
    rank: genus
61. Poecilia
    rank: genus
62. Ramnogaster
    rank: genus
63. Syngnathus
    rank: genus
64. Trachinotus
    rank: genus
65. Trichiurus
    rank: genus
66. Anchoa marinii
    rank: species
67. Brevoortia pectinata
    rank: species
68. Catathyridium garmani
    rank: species
69. Catathyridium jenynsii
    rank: species
70. Engraulis anchoita
    rank: species
71. Eucinostomus gula
    rank: species
72. Eucinostomus melanopterus
    rank: species
73. Gobiesox strumosus
    rank: species
74. Gobionellus oceanicus
    rank: species
75. Gobiosoma parri
    rank: species
76. Hyporhamphus roberti
    rank: species
77. Lycengraulis grossidens
    rank: species
78. Macrodon atricauda
    rank: species
79. Menticirrhus americanus
    rank: species
80. Micropogonias furnieri
    rank: species
81. Mugil cephalus
    rank: species
82. Mugil curema
    rank: species
83. Mugil liza
    rank: species
84. Mugil platanus
    rank: species
85. Paralichthys orbignyanus
    rank: species
86. Paralonchurus brasiliensis
    rank: species
87. Parapimelodus nigribarbis
    rank: species
88. Parona signata
    rank: species
89. Peprilus paru
    rank: species
90. Poecilia vivipara
    rank: species
91. Ramnogaster arcuata
    rank: species
92. Syngnathus folletti
    rank: species
93. Trachinotus goodei
    rank: species
94. Trichiurus lepturus
    rank: species

The Patos Lagoon located in the southern Brazilian coastal plain (Rio Grande do Sul state), is the largest (10,360 km2) choked lagoon in the world. It stretches in a NE SW direction from the city of Porto Alegre (30°30’ S) to Rio Grande (32°12’ S). In the south, an estuarine region of approximately 10 % of total area is connected by a single and narrow inlet to the Atlantic Ocean. The major tributary rivers in the northern and central areas of Patos Lagoon, and the São Gonçalo channel in the southern area, are significant freshwater sources from an extensive drainage basin. The hydrodynamics of Patos Lagoon estuary is strongly controlled by river discharge and the action of predominant winds. Ichthyoplankton samples were collected in shallow beaches in the estuary and in the adjacent coastal sandy beaches.