year species_id wgt_kg 63 1977 DM 0.040 64 1977 DM 0.048 65 1977 DM 0.029 66 1977 DM 0.046 67 1977 DM 0.036 68 1977 DO 0.052 69 1977 PF 0.008 70 1977 OX 0.022 71 1977 DM 0.035 74 1977 PF 0.007 75 1977 DM 0.022 78 1977 PF 0.009 79 1977 DM 0.042 81 1977 PF 0.008 82 1977 DM 0.041 83 1977 DM 0.037 84 1977 DM 0.043 85 1977 DM 0.041 86 1977 DM 0.040 87 1977 PF 0.009 88 1977 DM 0.045 89 1977 PP 0.015 90 1977 DM 0.029 92 1977 DM 0.039 93 1977 DM 0.042 ... [ reached 'max' / getOption("max.print") -- omitted 31950 rows ] year month day species_id 1 1977 7 17 SH 2 1978 11 4 SH 3 1982 5 21 SH 4 1982 6 29 SH 5 1983 3 14 SH 6 1983 4 16 SH 7 1986 10 4 SH 8 1987 7 26 SH 9 1987 8 26 SH 10 1987 10 24 SH 11 1987 10 25 SH 12 1987 11 21 SH 13 1988 1 23 SH 14 1988 1 24 SH 15 1988 2 21 SH 16 1988 2 22 SH 17 1988 2 22 SH 18 1988 3 20 SH 19 1988 3 21 SH 20 1988 4 18 SH 21 1988 4 19 SH 22 1988 4 19 SH 23 1988 5 14 SH 24 1988 5 14 SH 25 1988 5 15 SH ...