Eelgrass Trawling

Introduction

Eelgrass beds are important nursery areas for many nearshore and estuarine fishes. This monthly trawl survey examined the composition of fish species within two eelgrass beds. The first is located near the entrance of Humboldt Bay, CA (N 40° 46.39', W 124° 12.62'), and the second is located and at the north end of Indian Island in Humboldt Bay (N 40° 49' 00", W 124° 10' 28"). The Entrance Bay location was sampled from May 2003 until August 2008. Indian Island was sampled from January 2006 until February 2007. In March of 2007 a new location replaced the Indian Island location in Northern Humboldt Bay, CA (N 40.8198',W-124.1335'). This study shows the seasonal utilization of eelgrass beds by commercially and ecologically important fishes within Humboldt Bay. Data to date has shown that species abundance and diversity vary greatly between seasons. Species diversity and abundance is notably larger during the spring and summer. This is largely due to an increase in numbers of juvenile fishes, which emphasizes the importance of eelgrass beds as nursery areas. Strong interannual variation in species abundance is also evident.

Seagrass beds are known to have more species of fish, in greater abundance, than nearby bare substrates (Briggs & O'Conner, 1971; Orth & Heck, 1980). Different species associate with seagrass beds for different lengths of time or they may utilize them during different life history stages (Robblee & Zieman, 1984). For example, many species of fish utilize seagrass beds as juvenile nursery areas after settling out of the plankton (Adams, 1976). This study examines the diversity and abundance of fishes utilizing an eelgrass bed in Humboldt Bay, CA.

Imagery of Entrance Bay Study site.

Entrance Bay - Study site.

Methods

Repetitive trawl sampling was conducted over three eelgrass beds, Zostera marina, located in Entrance Bay, of Humboldt Bay, California (N 40° 46.394', W 124° 12.623'), at the north end of Indian Island (N 40° 49' 00", W 124° 10' 28") and at the eastern North bay (N 40.8198',W-124.1335'). Each eelgrass bed was sampled once per month with sampling starting in May 2003 for the Entrance Bay location, January 2006 for Indian Island and March 07 for North Bay. Sampling was conducted using a 16' epibenthic otter trawl towed from a 26' pontoon boat. The trawl consists of 1 inch stretch mesh with a 5 mm cod end lining. On each sampling date four trawls were conducted. Each trawl was approximately five minutes in length. Samples were taken in four to nine feet of water during both incoming and outgoing tides. The fishes collected were identified, enumerated, measured (total length), and released at site of capture.

Query the Dataset (Site 1: Entrance Bay)

By Species :

bat ray bay goby bay pipefish black rockfish bocaccio bony head sculpin brown irish lord buffalo sculpin cabezon california halibut clinidae spp. copper rockfish crevice kelpfish curlfin turbot english sole grass rockfish kelp greenling lingcod night smelt northern anchovy osmeridae spp. pacific herring pacific sardene padded sculpin penpoint gunnel pile surfperch red irish lord ringtail snailfish rockfish rockweed gunnel saddleback gunnel sand lance sand sole shiner surfperch silverspotted sculpin snailfish speckled sandab staghorn sculpin starry flounder steelhead stickleback striped surfperch surf smelt threespine stickleback topsmelt tubesnout unidentified unidentified flatfish unidentified gadid unknown smelt unkown sculpin walleye surfperch white surfperch

By Date :

May 2003 Jun 2003 Aug 2003 Sep 2003 Oct 2003 Nov 2003 Dec 2003 Jan 2004 Feb 2004 Mar 2004 Apr 2004 May 2004 Jun 2004 Jul 2004 Aug 2004 Sep 2004 Oct 2004 Nov 2004 Dec 2004 Jan 2005 Feb 2005 Mar 2005 Apr 2005 May 2005 Jun 2005 Jul 2005 Aug 2005 Sep 2005 Oct 2005 Nov 2005 Dec 2005 Jan 2006 Feb 2006 Mar 2006 Apr 2006 June 2006 July 2006 Sep 2006 Oct 2006 Nov 2006 Dec 2006 Jan 2007 Feb 2007 Mar 2007 Apr 2007 May 2007 June 2007 July 2007 Aug 2007 Sep 2007 Oct 2007 Nov 2007 Dec 2007 Jan 2008 Feb 2008 Mar 2008 Apr 2008 May 2008 Jun 2008 Jul 2008 Aug 2008

By Max Length :

bat ray bay goby bay pipefish black rockfish bocaccio bony head sculpin brown irish lord buffalo sculpin cabezon california halibut clinidae spp. copper rockfish crevice kelpfish curlfin turbot english sole grass rockfish kelp greenling lingcod night smelt northern anchovy osmeridae spp. pacific herring pacific sardene padded sculpin penpoint gunnel pile surfperch red irish lord ringtail snailfish rockfish rockweed gunnel saddleback gunnel sand lance sand sole shiner surfperch silverspotted sculpin snailfish speckled sandab staghorn sculpin starry flounder steelhead stickleback striped surfperch surf smelt threespine stickleback topsmelt tubesnout unidentified unidentified flatfish unidentified gadid unknown smelt unkown sculpin walleye surfperch white surfperch

Greater than less than

1 1 8 14 21 22 25 26 26 26 27 29 30 30 31 32 33 35 36 36 37 37 38 38 39 41 42 42 42 42 42 43 43 43 44 44 44 44 45 45 45 45 46 46 46 46 46 47 47 48 48 48 48 49 49 49 49 49 50 50 50 50 51 51 52 52 53 53 53 53 53 53 53 53 54 54 54 54 54 54 54 55 55 55 55 55 55 55 55 55 55 56 56 56 57 57 57 57 57 57 58 58 58 58 58 59 59 59 59 59 60 60 60 60 60 60 60 60 60 60 60 60 61 61 61 62 62 62 62 62 63 63 63 63 63 64 64 64 64 64 64 65 65 65 65 65 65 65 65 65 65 65 66 66 66 66 66 67 67 67 67 67 67 67 67 68 68 68 68 68 68 69 69 69 69 69 69 69 70 70 70 70 70 70 70 70 70 70 70 71 71 71 72 72 72 72 72 72 72 73 73 73 73 73 73 74 74 74 74 74 74 74 74 74 75 75 75 75 75 75 75 75 75 75 76 76 76 76 76 76 76 76 77 77 77 77 77 77 77 77 77 78 78 78 78 78 78 78 79 79 79 79 79 80 80 80 80 80 80 81 81 81 81 81 82 82 82 82 83 83 83 83 83 83 84 84 84 84 84 84 85 85 85 85 85 85 85 85 85 85 85 85 85 86 86 86 86 86 87 87 87 87 87 87 87 87 87 87 87 88 88 88 88 88 88 88 88 88 89 89 89 89 89 89 89 89 89 89 90 90 90 90 90 90 90 90 91 91 91 91 91 92 92 92 92 92 92 92 92 92 92 92 93 93 94 94 94 94 94 94 94 94 94 95 95 95 95 95 95 95 95 96 96 96 97 97 97 97 97 97 97 97 97 97 97 98 98 98 98 98 98 98 99 99 99 99 99 99 100 100 100 100 100 100 100 100 100 100 100 100 100 100 101 101 101 101 101 101 102 102 102 102 102 103 103 103 103 103 104 104 104 104 104 104 104 104 105 105 105 105 105 105 105 105 105 105 105 105 105 105 105 107 107 107 107 107 108 108 108 108 109 109 109 109 110 110 110 110 110 110 110 110 110 110 110 110 111 111 111 112 112 112 112 113 113 113 113 114 114 114 114 115 115 115 115 115 115 115 115 116 116 116 116 116 117 117 117 117 117 117 117 118 118 119 119 119 120 120 120 120 120 120 120 120 120 120 121 121 121 121 121 121 121 122 122 122 122 122 123 123 123 124 124 124 124 124 124 124 125 125 125 125 125 125 125 125 125 125 125 125 126 126 126 126 126 126 126 127 127 127 127 127 127 127 128 128 128 129 129 129 129 130 130 130 130 130 130 130 130 130 131 131 131 131 131 132 132 132 132 133 133 133 133 134 134 134 134 134 134 135 135 135 135 135 136 136 137 137 137 137 137 138 138 138 139 139 139 139 139 140 140 141 141 141 141 141 142 142 142 143 143 143 143 143 143 143 143 144 144 144 144 144 144 144 145 145 145 145 145 145 145 145 145 146 146 146 146 147 147 147 147 147 147 147 148 149 149 149 150 150 150 150 150 150 150 151 151 151 151 152 152 152 152 153 153 153 153 154 154 154 154 154 154 154 155 155 155 156 156 156 156 156 157 157 157 158 158 158 159 159 159 159 159 159 160 160 160 160 160 161 161 161 161 162 162 162 163 163 164 164 164 164 165 165 165 165 165 166 167 167 168 169 169 170 170 170 170 171 172 172 172 172 173 173 173 174 174 174 174 175 175 175 176 176 177 177 177 178 180 180 180 180 180 182 182 183 184 184 185 185 186 186 186 187 188 188 190 190 191 191 193 193 193 194 194 194 195 195 197 198 198 198 198 200 200 200 200 201 202 203 204 204 205 205 205 206 207 209 209 210 210 211 211 211 211 212 213 215 215 215 216 216 217 218 219 220 221 224 225 225 225 226 226 228 228 228 229 230 230 230 235 235 236 237 238 238 239 240 240 240 240 240 240 242 242 243 243 245 246 246 246 246 246 246 248 250 251 252 254 256 257 257 257 257 259 260 260 262 262 262 263 265 265 265 266 266 267 268 269 270 273 274 274 274 275 276 276 280 280 280 280 281 282 282 282 283 284 284 284 285 285 285 285 286 286 287 287 287 288 288 288 288 290 290 291 291 291 293 295 295 295 297 298 299 299 300 300 300 300 301 302 302 303 303 303 306 306 306 307 307 308 308 310 310 310 310 310 310 312 312 314 314 314 315 316 318 320 320 321 321 322 324 324 327 330 330 330 330 332 333 334 334 335 335 340 340 340 343 344 345 345 346 349 350 350 354 358 360 361 369 370 370 377 382 397 400 404 405 410 422 423 440 460 512 620

Query the Dataset (Site 2: Indian Island )

By Species :

arrow goby bay goby bay pipefish cabezon chinook salmon english sole goby spp. northern anchovy osmeridae spp. pacific herring penpoint gunnel pile surfperch plainfin midshipmen redtail surfperch rockweed gunnel saddleback gunnel sand sole shiner surfperch speckled sandab staghorn sculpin starry flounder striped surfperch surf smelt threespine stickleback topsmelt tubesnout walleye surfperch white surfperch

By Date :

Jan 2006 Feb 2006 Mar 2006 Apr 2006 June 2006 July 2006 Sep 2006 Oct 2006 Nov 2006 Dec 2006 Jan 2007 Feb 2007

By Max Length :

arrow goby bay goby bay pipefish cabezon chinook salmon english sole goby spp. northern anchovy osmeridae spp. pacific herring penpoint gunnel pile surfperch plainfin midshipmen redtail surfperch rockweed gunnel saddleback gunnel sand sole shiner surfperch speckled sandab staghorn sculpin starry flounder striped surfperch surf smelt threespine stickleback topsmelt tubesnout walleye surfperch white surfperch

Greater than less than

1 1 8 14 21 22 25 26 26 26 27 29 30 30 31 32 33 35 36 36 37 37 38 38 39 41 42 42 42 42 42 43 43 43 44 44 44 44 45 45 45 45 46 46 46 46 46 47 47 48 48 48 48 49 49 49 49 49 50 50 50 50 51 51 52 52 53 53 53 53 53 53 53 53 54 54 54 54 54 54 54 55 55 55 55 55 55 55 55 55 55 56 56 56 57 57 57 57 57 57 58 58 58 58 58 59 59 59 59 59 60 60 60 60 60 60 60 60 60 60 60 60 61 61 61 62 62 62 62 62 63 63 63 63 63 64 64 64 64 64 64 65 65 65 65 65 65 65 65 65 65 65 66 66 66 66 66 67 67 67 67 67 67 67 67 68 68 68 68 68 68 69 69 69 69 69 69 69 70 70 70 70 70 70 70 70 70 70 70 71 71 71 72 72 72 72 72 72 72 73 73 73 73 73 73 74 74 74 74 74 74 74 74 74 75 75 75 75 75 75 75 75 75 75 76 76 76 76 76 76 76 76 77 77 77 77 77 77 77 77 77 78 78 78 78 78 78 78 79 79 79 79 79 80 80 80 80 80 80 81 81 81 81 81 82 82 82 82 83 83 83 83 83 83 84 84 84 84 84 84 85 85 85 85 85 85 85 85 85 85 85 85 85 86 86 86 86 86 87 87 87 87 87 87 87 87 87 87 87 88 88 88 88 88 88 88 88 88 89 89 89 89 89 89 89 89 89 89 90 90 90 90 90 90 90 90 91 91 91 91 91 92 92 92 92 92 92 92 92 92 92 92 93 93 94 94 94 94 94 94 94 94 94 95 95 95 95 95 95 95 95 96 96 96 97 97 97 97 97 97 97 97 97 97 97 98 98 98 98 98 98 98 99 99 99 99 99 99 100 100 100 100 100 100 100 100 100 100 100 100 100 100 101 101 101 101 101 101 102 102 102 102 102 103 103 103 103 103 104 104 104 104 104 104 104 104 105 105 105 105 105 105 105 105 105 105 105 105 105 105 105 107 107 107 107 107 108 108 108 108 109 109 109 109 110 110 110 110 110 110 110 110 110 110 110 110 111 111 111 112 112 112 112 113 113 113 113 114 114 114 114 115 115 115 115 115 115 115 115 116 116 116 116 116 117 117 117 117 117 117 117 118 118 119 119 119 120 120 120 120 120 120 120 120 120 120 121 121 121 121 121 121 121 122 122 122 122 122 123 123 123 124 124 124 124 124 124 124 125 125 125 125 125 125 125 125 125 125 125 125 126 126 126 126 126 126 126 127 127 127 127 127 127 127 128 128 128 129 129 129 129 130 130 130 130 130 130 130 130 130 131 131 131 131 131 132 132 132 132 133 133 133 133 134 134 134 134 134 134 135 135 135 135 135 136 136 137 137 137 137 137 138 138 138 139 139 139 139 139 140 140 141 141 141 141 141 142 142 142 143 143 143 143 143 143 143 143 144 144 144 144 144 144 144 145 145 145 145 145 145 145 145 145 146 146 146 146 147 147 147 147 147 147 147 148 149 149 149 150 150 150 150 150 150 150 151 151 151 151 152 152 152 152 153 153 153 153 154 154 154 154 154 154 154 155 155 155 156 156 156 156 156 157 157 157 158 158 158 159 159 159 159 159 159 160 160 160 160 160 161 161 161 161 162 162 162 163 163 164 164 164 164 165 165 165 165 165 166 167 167 168 169 169 170 170 170 170 171 172 172 172 172 173 173 173 174 174 174 174 175 175 175 176 176 177 177 177 178 180 180 180 180 180 182 182 183 184 184 185 185 186 186 186 187 188 188 190 190 191 191 193 193 193 194 194 194 195 195 197 198 198 198 198 200 200 200 200 201 202 203 204 204 205 205 205 206 207 209 209 210 210 211 211 211 211 212 213 215 215 215 216 216 217 218 219 220 221 224 225 225 225 226 226 228 228 228 229 230 230 230 235 235 236 237 238 238 239 240 240 240 240 240 240 242 242 243 243 245 246 246 246 246 246 246 248 250 251 252 254 256 257 257 257 257 259 260 260 262 262 262 263 265 265 265 266 266 267 268 269 270 273 274 274 274 275 276 276 280 280 280 280 281 282 282 282 283 284 284 284 285 285 285 285 286 286 287 287 287 288 288 288 288 290 290 291 291 291 293 295 295 295 297 298 299 299 300 300 300 300 301 302 302 303 303 303 306 306 306 307 307 308 308 310 310 310 310 310 310 312 312 314 314 314 315 316 318 320 320 321 321 322 324 324 327 330 330 330 330 332 333 334 334 335 335 340 340 340 343 344 345 345 346 349 350 350 354 358 360 361 369 370 370 377 382 397 400 404 405 410 422 423 440 460 512 620

Query the Dataset (Site 3: North Bay)

By Species :

arrow goby bat ray bay pipefish black rockfish cabezon california halibut copper rockfish english sole kelp greenling lingcod northern anchovy osmeridae spp. pacific herring penpoint gunnel pile surfperch redtail surfperch saddleback gunnel shiner surfperch silverspotted sculpin speckled sandab staghorn sculpin starry flounder stickleback striped surfperch surf smelt threespine stickleback topsmelt tubesnout unidentified flatfish walleye surfperch white surfperch

By Date :

April 2007 May 2007 June 2007 July 2007 Aug 2007 Sep 2007 Oct 2007 Nov 2007 Dec 2007 Jan 2008 Feb 2008 Mar 2008 Apr 2008 May 2008 Jun 2008 Jul 2008 Aug 2008 Mar 2007

By Max Length :

arrow goby bat ray bay pipefish black rockfish cabezon california halibut copper rockfish english sole kelp greenling lingcod northern anchovy osmeridae spp. pacific herring penpoint gunnel pile surfperch redtail surfperch saddleback gunnel shiner surfperch silverspotted sculpin speckled sandab staghorn sculpin starry flounder stickleback striped surfperch surf smelt threespine stickleback topsmelt tubesnout unidentified flatfish walleye surfperch white surfperch

Greater than less than

1 1 8 14 21 22 25 26 26 26 27 29 30 30 31 32 33 35 36 36 37 37 38 38 39 41 42 42 42 42 42 43 43 43 44 44 44 44 45 45 45 45 46 46 46 46 46 47 47 48 48 48 48 49 49 49 49 49 50 50 50 50 51 51 52 52 53 53 53 53 53 53 53 53 54 54 54 54 54 54 54 55 55 55 55 55 55 55 55 55 55 56 56 56 57 57 57 57 57 57 58 58 58 58 58 59 59 59 59 59 60 60 60 60 60 60 60 60 60 60 60 60 61 61 61 62 62 62 62 62 63 63 63 63 63 64 64 64 64 64 64 65 65 65 65 65 65 65 65 65 65 65 66 66 66 66 66 67 67 67 67 67 67 67 67 68 68 68 68 68 68 69 69 69 69 69 69 69 70 70 70 70 70 70 70 70 70 70 70 71 71 71 72 72 72 72 72 72 72 73 73 73 73 73 73 74 74 74 74 74 74 74 74 74 75 75 75 75 75 75 75 75 75 75 76 76 76 76 76 76 76 76 77 77 77 77 77 77 77 77 77 78 78 78 78 78 78 78 79 79 79 79 79 80 80 80 80 80 80 81 81 81 81 81 82 82 82 82 83 83 83 83 83 83 84 84 84 84 84 84 85 85 85 85 85 85 85 85 85 85 85 85 85 86 86 86 86 86 87 87 87 87 87 87 87 87 87 87 87 88 88 88 88 88 88 88 88 88 89 89 89 89 89 89 89 89 89 89 90 90 90 90 90 90 90 90 91 91 91 91 91 92 92 92 92 92 92 92 92 92 92 92 93 93 94 94 94 94 94 94 94 94 94 95 95 95 95 95 95 95 95 96 96 96 97 97 97 97 97 97 97 97 97 97 97 98 98 98 98 98 98 98 99 99 99 99 99 99 100 100 100 100 100 100 100 100 100 100 100 100 100 100 101 101 101 101 101 101 102 102 102 102 102 103 103 103 103 103 104 104 104 104 104 104 104 104 105 105 105 105 105 105 105 105 105 105 105 105 105 105 105 107 107 107 107 107 108 108 108 108 109 109 109 109 110 110 110 110 110 110 110 110 110 110 110 110 111 111 111 112 112 112 112 113 113 113 113 114 114 114 114 115 115 115 115 115 115 115 115 116 116 116 116 116 117 117 117 117 117 117 117 118 118 119 119 119 120 120 120 120 120 120 120 120 120 120 121 121 121 121 121 121 121 122 122 122 122 122 123 123 123 124 124 124 124 124 124 124 125 125 125 125 125 125 125 125 125 125 125 125 126 126 126 126 126 126 126 127 127 127 127 127 127 127 128 128 128 129 129 129 129 130 130 130 130 130 130 130 130 130 131 131 131 131 131 132 132 132 132 133 133 133 133 134 134 134 134 134 134 135 135 135 135 135 136 136 137 137 137 137 137 138 138 138 139 139 139 139 139 140 140 141 141 141 141 141 142 142 142 143 143 143 143 143 143 143 143 144 144 144 144 144 144 144 145 145 145 145 145 145 145 145 145 146 146 146 146 147 147 147 147 147 147 147 148 149 149 149 150 150 150 150 150 150 150 151 151 151 151 152 152 152 152 153 153 153 153 154 154 154 154 154 154 154 155 155 155 156 156 156 156 156 157 157 157 158 158 158 159 159 159 159 159 159 160 160 160 160 160 161 161 161 161 162 162 162 163 163 164 164 164 164 165 165 165 165 165 166 167 167 168 169 169 170 170 170 170 171 172 172 172 172 173 173 173 174 174 174 174 175 175 175 176 176 177 177 177 178 180 180 180 180 180 182 182 183 184 184 185 185 186 186 186 187 188 188 190 190 191 191 193 193 193 194 194 194 195 195 197 198 198 198 198 200 200 200 200 201 202 203 204 204 205 205 205 206 207 209 209 210 210 211 211 211 211 212 213 215 215 215 216 216 217 218 219 220 221 224 225 225 225 226 226 228 228 228 229 230 230 230 235 235 236 237 238 238 239 240 240 240 240 240 240 242 242 243 243 245 246 246 246 246 246 246 248 250 251 252 254 256 257 257 257 257 259 260 260 262 262 262 263 265 265 265 266 266 267 268 269 270 273 274 274 274 275 276 276 280 280 280 280 281 282 282 282 283 284 284 284 285 285 285 285 286 286 287 287 287 288 288 288 288 290 290 291 291 291 293 295 295 295 297 298 299 299 300 300 300 300 301 302 302 303 303 303 306 306 306 307 307 308 308 310 310 310 310 310 310 312 312 314 314 314 315 316 318 320 320 321 321 322 324 324 327 330 330 330 330 332 333 334 334 335 335 340 340 340 343 344 345 345 346 349 350 350 354 358 360 361 369 370 370 377 382 397 400 404 405 410 422 423 440 460 512 620

Download

Latest Datasets:
Entrance Bay Data May 2003 -- Feb 2006
Woodley Island Data Jan 2006 -- Feb 2006

Literature Cited

Adams, S. 1976. The ecology of eelgrass Zostera marina fish communities. Journal of Experimental Marine Biology and Ecology. 22, 269-91.

Briggs, P. & J. O'Connor. 1971. Comparison of shore-zone fishes over naturally vegetated and sand-filled bottoms in Great South Bay. New York Fish and Game Journal. 18, 15-41.

Orth, R. & K. Heck. 1980. Structural componenets of the eelgrass (Zostera marina) meadows in the lower Chesapeake Bay fishes. Estuaries. 3, 278-88.

Robblee, M. & J. Zieman. 1984. Diel variation in the fish fauna of a tropical seagrass feeding ground. Bulletin of Marine Science. 34, 335-45.

Project Leaders - contact

Dr. Tim Mulligan - tjm2@humboldt.edu
Rebecca Studebaker - rss15@humboldt.edu